1
|
García-Alfonso E, Barranco M, Halberstadt N, Pi M. Time-resolved solvation of alkali ions in superfluid helium nanodroplets. J Chem Phys 2024; 160:164308. [PMID: 38651804 DOI: 10.1063/5.0205951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 03/29/2024] [Indexed: 04/25/2024] Open
Abstract
The sinking of alkali cations in superfluid 4He nanodroplets is investigated theoretically using liquid 4He time-dependent density functional theory at zero temperature. The simulations illustrate the dynamics of the buildup of the first solvation shell around the ions. The number of helium atoms in this shell is found to linearly increase with time during the first stages of the dynamics. This points to a Poissonian capture process, as concluded in the work of Albrechtsen et al. on the primary steps of Na+ solvation in helium droplets [Albrechtsen et al., Nature 623, 319 (2023)]. The energy dissipation rate by helium atom ejection is found to be quite similar between all alkalis, the main difference being a larger energy dissipated per atom for the lighter alkalis at the beginning of the dynamics. In addition, the number of helium atoms in the first solvation shell is found to be lower at the end of the dynamics than at equilibrium for both Li+ and Na+, pointing to a kinetic rather than thermodynamical control of the snowball size for small and strongly attractive ions.
Collapse
Affiliation(s)
- Ernesto García-Alfonso
- Laboratoire Collisions, Agrégats, Réactivité (LCAR), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Manuel Barranco
- Departament FQA, Facultat de Física, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
| | - Nadine Halberstadt
- Laboratoire Collisions, Agrégats, Réactivité (LCAR), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Martí Pi
- Departament FQA, Facultat de Física, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
| |
Collapse
|
2
|
Miyazaki M, Ono M, Otsuka R, Dopfer O, Fujii M. Electronic and vibrational spectroscopies of aromatic clusters with He in a supersonic jet: The case of neutral and cationic phenol-Hen (n = 1 and 2). J Chem Phys 2023; 159:134303. [PMID: 37787127 DOI: 10.1063/5.0169716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 09/15/2023] [Indexed: 10/04/2023] Open
Abstract
Van der Waals clusters composed of He and aromatic molecules provide fundamental information about intermolecular interactions in weakly bound systems. In this study, phenol-helium clusters (PhOH-Hen with n ≤ 2) are characterized for the first time by UV and IR spectroscopies. The S1 ← S0 origin and ionization energy both show small but additive shifts, suggesting π-bound structures of these clusters, a conclusion supported by rotational contour analyses of the S1 origin bands. The OH stretching vibrations of the PhOH moiety in the clusters match with those of bare PhOH in both the S0 and D0 states, illustrating the negligible perturbation of the He atoms on the molecular vibration. Matrix shifts induced by He attachment are discussed based on the observed band positions with the help of complementary quantum chemical calculations. For comparison, the UV and ionization spectra of PhOH-Ne are reported as well.
Collapse
Affiliation(s)
- Mitsuhiko Miyazaki
- Natural Science Division, Faculty of Core Research, Ochanomizu University, 2-1-1 Ohtsuka, Bunkyo-ku, Tokyo 112-8610, Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Megumi Ono
- School of Life Science and Technology, Tokyo Institute of Technology, 4259, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Remina Otsuka
- School of Life Science and Technology, Tokyo Institute of Technology, 4259, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Otto Dopfer
- Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany
- International Research Frontiers Initiative (IRFI), Institute of Innovation Research, Tokyo Institute of Technology, 4259, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Masaaki Fujii
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, 4259, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- International Research Frontiers Initiative (IRFI), Institute of Innovation Research, Tokyo Institute of Technology, 4259, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| |
Collapse
|
3
|
Zunzunegui-Bru E, Gruber E, Lázaro T, Bartolomei M, Hernández MI, Campos-Martínez J, González-Lezana T, Bergmeister S, Zappa F, Scheier P, Pérez de Tudela R, Hernández-Rojas J, Bretón J. Observation of Multiple Ordered Solvation Shells in Doped Helium Droplets: The Case of He NCa 2. J Phys Chem Lett 2023; 14:3126-3131. [PMID: 36952614 PMCID: PMC10084467 DOI: 10.1021/acs.jpclett.3c00224] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In this Letter, we report the experimental detection of likely the largest ordered structure of helium atoms surrounding a monatomic impurity observed to date using a recently developed technique. The mass spectrometry investigation of HeNCa2+ clusters, formed in multiply charged helium nanodroplets, reveals magic numbers at N = 12, 32, 44, and 74. Classical optimization and path integral Monte Carlo calculations suggest the existence of up to four shells surrounding the calcium dication which are closed with well-ordered Mozartkugel-like structures: He12Ca2+ with an icosahedron, the second at He32Ca2+ with a dodecahedron, the third at He44Ca2+ with a larger icosahedron, and finally for He74Ca2+, we find that the outermost He atoms form an icosidodecahedron which contains the other inner shells. We analyze the reasons for the formation of such ordered shells in order to guide the selection of possible candidates to exhibit a similar behavior.
Collapse
Affiliation(s)
- Eva Zunzunegui-Bru
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, Madrid 28006, Spain
| | - Elisabeth Gruber
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
| | - Teresa Lázaro
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, Madrid 28006, Spain
| | | | - Marta I Hernández
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, Madrid 28006, Spain
| | | | | | - Stefan Bergmeister
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
| | - Fabio Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
| | | | - Javier Hernández-Rojas
- Departamento de Física and IUdEA, Universidad de La Laguna, La Laguna, 38205, Tenerife, Spain
| | - José Bretón
- Departamento de Física and IUdEA, Universidad de La Laguna, La Laguna, 38205, Tenerife, Spain
| |
Collapse
|
4
|
Lushchikova OV, Gatchell M, Reichegger J, Kollotzek S, Zappa F, Mahmoodi-Darian M, Scheier P. Structure and formation of copper cluster ions in multiply charged He nanodroplets. Phys Chem Chem Phys 2023; 25:8463-8471. [PMID: 36916872 PMCID: PMC10032196 DOI: 10.1039/d2cp04569a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
The structure of cationic and anionic Cu clusters grown in multiply charged superfluid He nanodroplets was investigated using He tagging as a chemical probe. Further, the structure assignment was done based on the magic-numbered ions, representing the most energetically favorable structures. The exact geometry of the cluster and positions of He is verified by calculations. It was found that the structure of the clusters grown in the He droplets is similar to that produced with a laser ablation source and the lowest energy structures predicted by theoretical investigations. The only difference is the structure of the Cu5+, which in our experiments has a twisted-X geometry, rather than a bipyramid or planar half-wheel geometry suggested by previous studies. This might be attributed to the different cluster formation mechanisms, the absence of the Ar-tag and the ultracold environment. It was also found that He tends to bind to partially more electro-negative or positive areas of the anionic or cationic clusters, respectively.
Collapse
Affiliation(s)
- O V Lushchikova
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - M Gatchell
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - J Reichegger
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - S Kollotzek
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - F Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - M Mahmoodi-Darian
- Department of Physics, Karaj Branch, Islamic Azad University, Karaj, Iran
| | - P Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| |
Collapse
|
5
|
Alić J, Messner R, Alešković M, Küstner F, Rubčić M, Lackner F, Ernst WE, Šekutor M. Diamondoid ether clusters in helium nanodroplets. Phys Chem Chem Phys 2023; 25:11951-11958. [PMID: 36942672 PMCID: PMC10155488 DOI: 10.1039/d3cp00489a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
Diamondoid ethers were introduced into superfluid helium nanodroplets and the resulting clusters were analyzed by time-of-flight mass spectrometry. Clusters of higher abundances (magic number clusters) were identified and the corresponding potential cluster geometries were obtained from GFN2-xTB and DFT computations. We found that the studied diamondoid ethers readily self-assemble in helium nanodroplets and that London dispersion attraction between hydrocarbon subunits acts as a driving force for cluster formation. On the other hand, hydrogen bonding between ether oxygens and trace water molecules fosters the eventual breakdown of the initial supramolecular aggregate.
Collapse
Affiliation(s)
- Jasna Alić
- Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia.
| | - Roman Messner
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria.
| | - Marija Alešković
- Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia.
| | - Florian Küstner
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria.
| | - Mirta Rubčić
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia
| | - Florian Lackner
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria.
| | - Wolfgang E Ernst
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria.
| | - Marina Šekutor
- Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia.
| |
Collapse
|
6
|
Vilà A, González M. Quantum dynamics of the Br 2 (B-excited state) photodissociation in superfluid helium nanodroplets: importance of the recombination process. Phys Chem Chem Phys 2022; 24:24353-24361. [PMID: 36178095 DOI: 10.1039/d2cp02984g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have studied the Br2 photodissociation dynamics (B ← X electronic transition) of Br2(v = 0, X)@(4He)N doped nanodroplets (T = 0.37 K) at zero angular momentum, with N in the 100-1000 interval. To do this, we have used a quantum mechanical hybrid strategy proposed by us and, as far as we know, this is the second quantum dynamics study available on the photodissociation of molecules in superfluid helium nanodroplets. While the results obtained for some properties are qualitatively similar to those reported previously by us for the Cl2(B ← X) related case (in particular, the oscillating Br final velocity distribution which also arises from quantum interferences), large differences are evident in three key properties: the photodissociation mechanism and probability and the time scale of the process. This can be interpreted on the basis of the significantly lower excitation energy achieved by the Br2(B ← X) transition and the higher reduced mass of Br-Br in comparison to the chlorine case. The Br2(B) photodissociation dynamics is significantly more complex than that of Cl2(B) and leads to the fragmentation of the initial wave packet. Thus, the probability of non-dissociation is equal to 17, 18, 51, 85 and 100% for N = 100, 200, 300, 500 and 1000, respectively, while for chlorine this probability is equal to zero. In spite of the very large experimental difficulties that exist for obtaining nanodroplets with a well defined size, we hope that these results will encourage experimentalists to investigate these interesting systems.
Collapse
Affiliation(s)
- Arnau Vilà
- Departament de Ciència dels Materials i Química Física and IQTC, Universitat de Barcelona, Martí i Franquès, 1-11, 08028 Barcelona, Spain.
| | - Miguel González
- Departament de Ciència dels Materials i Química Física and IQTC, Universitat de Barcelona, Martí i Franquès, 1-11, 08028 Barcelona, Spain.
| |
Collapse
|
7
|
Kazak L, Meiwes-Broer KH, Tiggesbäumker J. Ionization potentials of Mg N ( N = 7-56) clusters formed by spontaneous collapse of magnesium foam in helium nanodroplets. Phys Chem Chem Phys 2022; 24:23350-23356. [PMID: 36134466 DOI: 10.1039/d2cp03075f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ionization potentials of magnesium clusters (MgN, N = 7-56) are determined by doping ultracold helium nanodroplets (HeM, M ≈ 52 000) with Mg atoms. Inspecting the particle size distributions resulting from non-resonant, short-wavelength, single-photon ionization gives evidence that beyond a certain ensemble size, the developing foam structure undergoes a spontaneous collapse on the way to the laser interaction region. As a result, hot Mg clusters form in the relaxation process. The spontaneous collapse manifests in a substantial change in the size distributions, when recording mass spectra at wavelengths shorter than 272 nm. Tracing individual MgN signals as a function of laser photon energy allows extraction of size-specific ionization potentials, which for small clusters show a good agreement with results obtained from density functional theory simulations. The further development is compared to calculations based on the liquid drop model. However, even when quantum effects are included, the simple scaling law is not able to reproduce the development of the ionization potentials. The results suggest that small neutral magnesium clusters behave as non-metallic. The comparison to electron affinities and band gaps obtained from photoemission experiments on MgN- provides information on the charge state dependence of the non-metal-to-metal transition and properties like the Mulliken electron negativity.
Collapse
Affiliation(s)
- Lev Kazak
- Institute of Physics, University of Rostock, 18059, Rostock, Germany.
| | - Karl-Heinz Meiwes-Broer
- Institute of Physics, University of Rostock, 18059, Rostock, Germany. .,Department "Life, Light and Matter", University of Rostock, 18059, Rostock, Germany
| | - Josef Tiggesbäumker
- Institute of Physics, University of Rostock, 18059, Rostock, Germany. .,Department "Life, Light and Matter", University of Rostock, 18059, Rostock, Germany
| |
Collapse
|
8
|
García-Alfonso E, Barranco M, Bonhommeau DA, Halberstadt N, Pi M, Calvo F. Clustering, collision, and relaxation dynamics in pure and doped helium nanoclusters: Density- vs particle-based approaches. J Chem Phys 2022; 157:014106. [DOI: 10.1063/5.0091942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The clustering, collision, and relaxation dynamics of pristine and doped helium nanodroplets is theoretically investigated in cases of pickup and clustering of heliophilic argon, collision of heliophobic cesium atoms, and coalescence of two droplets brought into contact by their mutual long-range van der Waals interaction. Three approaches are used and compared with each other. The He time-dependent density functional theory method considers the droplet as a continuous medium and accounts for its superfluid character. The ring-polymer molecular dynamics method uses a path-integral description of nuclear motion and incorporates zero-point delocalization while bosonic exchange effects are ignored. Finally, the zero-point averaged dynamics approach is a mixed quantum–classical method in which quantum delocalization is described by attaching a frozen wavefunction to each He atom, equivalent to classical dynamics with effective interaction potentials. All three methods predict that the growth of argon clusters is significantly hindered by the helium host droplet due to the impeding shell structure around the dopants and kinematic effects freezing the growing cluster in metastable configurations. The effects of superfluidity are qualitatively manifested by different collision dynamics of the heliophilic atom at high velocities, as well as quadrupole oscillations that are not seen with particle-based methods, for droplets experiencing a collision with cesium atoms or merging with each other.
Collapse
Affiliation(s)
- Ernesto García-Alfonso
- Laboratoire Collisions, Agrégats, Réactivité (LCAR), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Manuel Barranco
- Laboratoire Collisions, Agrégats, Réactivité (LCAR), Université de Toulouse, CNRS, 31062 Toulouse, France
- Department FQA, Facultat de Física, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
| | - David A. Bonhommeau
- Université de Reims Champagne Ardenne, CNRS, GSMA UMR 7331, 51100 Reims, France
| | - Nadine Halberstadt
- Laboratoire Collisions, Agrégats, Réactivité (LCAR), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Martí Pi
- Department FQA, Facultat de Física, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
| | - Florent Calvo
- Université Grenoble Alpes, CNRS, LIPHY, F38000 Grenoble, France
| |
Collapse
|
9
|
Albertini S, Gruber E, Zappa F, Krasnokutski S, Laimer F, Scheier P. Chemistry and physics of dopants embedded in helium droplets. MASS SPECTROMETRY REVIEWS 2022; 41:529-567. [PMID: 33993543 DOI: 10.1002/mas.21699] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/20/2021] [Accepted: 04/20/2021] [Indexed: 05/18/2023]
Abstract
Helium droplets represent a cold inert matrix, free of walls with outstanding properties to grow complexes and clusters at conditions that are perfect to simulate cold and dense regions of the interstellar medium. At sub-Kelvin temperatures, barrierless reactions triggered by radicals or ions have been observed and studied by optical spectroscopy and mass spectrometry. The present review summarizes developments of experimental techniques and methods and recent results they enabled.
Collapse
Affiliation(s)
- Simon Albertini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
| | - Elisabeth Gruber
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
| | - Fabio Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
| | - Serge Krasnokutski
- Laboratory Astrophysics Group of the MPI for Astronomy, University of Jena, Jena, Germany
| | - Felix Laimer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
| |
Collapse
|
10
|
Briant M, Mestdagh JM, Gaveau MA, Poisson L. Reaction dynamics within a cluster environment. Phys Chem Chem Phys 2022; 24:9807-9835. [PMID: 35441619 DOI: 10.1039/d1cp05783a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This perspective article reviews experimental and theoretical works where rare gas clusters and helium nanodroplets are used as a nanoreactor to investigate chemical dynamics in a solvent environment. A historical perspective is presented first followed by specific considerations on the mobility of reactants within these reaction media. The dynamical response of pure clusters and nanodroplets to photoexcitation is shortly reviewed before examining the role of the cluster (or nanodroplet) degrees of freedom in the photodynamics of the guest atoms and molecules.
Collapse
Affiliation(s)
- Marc Briant
- Université Paris-Saclay, CEA, CNRS, LIDYL, 91191, Gif-sur-Yvette, France
| | | | - Marc-André Gaveau
- Université Paris-Saclay, CEA, CNRS, LIDYL, 91191, Gif-sur-Yvette, France
| | - Lionel Poisson
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405, Orsay, France.
| |
Collapse
|
11
|
Niman JW, Kamerin BS, Villers TH, Linker TM, Nakano A, Kresin VV. Probing the presence and absence of metal-fullerene electron transfer reactions in helium nanodroplets by deflection measurements. Phys Chem Chem Phys 2022; 24:10378-10383. [PMID: 35438706 DOI: 10.1039/d2cp00751g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Metal-fullerene compounds are characterized by significant electron transfer to the fullerene cage, giving rise to an electric dipole moment. We use the method of electrostatic beam deflection to verify whether such reactions take place within superfluid helium nanodroplets between an embedded C60 molecule and either alkali (heliophobic) or rare-earth (heliophilic) atoms. The two cases lead to distinctly different outcomes: C60Nan (n = 1-4) display no discernable dipole moment, while C60Yb is strongly polar. This suggests that the fullerene and small alkali clusters fail to form a charge-transfer bond in the helium matrix despite their strong van der Waals attraction. The C60Yb dipole moment, on the other hand, is in agreement with the value expected for an ionic complex.
Collapse
Affiliation(s)
- John W Niman
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484, USA.
| | - Benjamin S Kamerin
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484, USA.
| | - Thomas H Villers
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484, USA.
| | - Thomas M Linker
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA 90089-0242, USA
| | - Aiichiro Nakano
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA 90089-0242, USA
| | - Vitaly V Kresin
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484, USA.
| |
Collapse
|
12
|
Krebs BS, Tulsky V, Kazak L, Zabel M, Bauer D, Tiggesbäumker J. Phase-of-the-Phase Electron Momentum Spectroscopy on Single Metal Atoms in Helium Nanodroplets. J Phys Chem Lett 2022; 13:1526-1532. [PMID: 35133167 DOI: 10.1021/acs.jpclett.2c00110] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Magnesium atoms fully embedded in helium nanodroplets are exposed to two-color laser pulses, which trigger multiphoton above-threshold ionization (ATI). This allows exemplary study of the contribution of a dense, neutral, and finite medium on single electron propagation. The angular-resolved photoelectron spectra show striking differences with respect to results obtained on free atoms. Scattering of the individual Mg photoelectrons, when traversing the neutral helium environment, causes the angular distribution to become almost isotropic. Furthermore, the appearance of higher-energy electrons is observed, indicating the impact of the droplet on the concerted emission process. Phase-of-the-phase spectroscopy, however, reveals a marked loss in the 2ω-ω phase dependence of the electron signal. Taking into account sideband formation on a quantitative level, a Monte Carlo simulation which includes laser-assisted electron scattering can reproduce the experimental spectra and give insights into the strong-field-induced electron emission from disordered systems.
Collapse
Affiliation(s)
- Bennet S Krebs
- Institute of Physics, University of Rostock, 18059 Rostock, Germany
- Department "Life, Light and Matter", University of Rostock, 18059 Rostock, Germany
| | - Vasily Tulsky
- Institute of Physics, University of Rostock, 18059 Rostock, Germany
| | - Lev Kazak
- Institute of Physics, University of Rostock, 18059 Rostock, Germany
| | - Michael Zabel
- Institute of Physics, University of Rostock, 18059 Rostock, Germany
- Department "Life, Light and Matter", University of Rostock, 18059 Rostock, Germany
| | - Dieter Bauer
- Institute of Physics, University of Rostock, 18059 Rostock, Germany
| | - Josef Tiggesbäumker
- Institute of Physics, University of Rostock, 18059 Rostock, Germany
- Department "Life, Light and Matter", University of Rostock, 18059 Rostock, Germany
| |
Collapse
|
13
|
Tanyag RMP, Bacellar C, Pang W, Bernando C, Gomez LF, Jones CF, Ferguson KR, Kwok J, Anielski D, Belkacem A, Boll R, Bozek J, Carron S, Chen G, Delmas T, Englert L, Epp SW, Erk B, Foucar L, Hartmann R, Hexemer A, Huth M, Leone SR, Ma JH, Marchesini S, Neumark DM, Poon BK, Prell J, Rolles D, Rudek B, Rudenko A, Seifrid M, Swiggers M, Ullrich J, Weise F, Zwart P, Bostedt C, Gessner O, Vilesov AF. Sizes of pure and doped helium droplets from single shot x-ray imaging. J Chem Phys 2022; 156:041102. [PMID: 35105059 DOI: 10.1063/5.0080342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Advancements in x-ray free-electron lasers on producing ultrashort, ultrabright, and coherent x-ray pulses enable single-shot imaging of fragile nanostructures, such as superfluid helium droplets. This imaging technique gives unique access to the sizes and shapes of individual droplets. In the past, such droplet characteristics have only been indirectly inferred by ensemble averaging techniques. Here, we report on the size distributions of both pure and doped droplets collected from single-shot x-ray imaging and produced from the free-jet expansion of helium through a 5 μm diameter nozzle at 20 bars and nozzle temperatures ranging from 4.2 to 9 K. This work extends the measurement of large helium nanodroplets containing 109-1011 atoms, which are shown to follow an exponential size distribution. Additionally, we demonstrate that the size distributions of the doped droplets follow those of the pure droplets at the same stagnation condition but with smaller average sizes.
Collapse
Affiliation(s)
- Rico Mayro P Tanyag
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Camila Bacellar
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Weiwu Pang
- Department of Computer Science, University of Southern California, Los Angeles, California 90089, USA
| | - Charles Bernando
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, USA
| | - Luis F Gomez
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Curtis F Jones
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Ken R Ferguson
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Justin Kwok
- Department of Chemical Engineering and Material Science, University of Southern California, Los Angeles, California 90089, USA
| | - Denis Anielski
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Ali Belkacem
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Rebecca Boll
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - John Bozek
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Sebastian Carron
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Gang Chen
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Tjark Delmas
- Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany
| | - Lars Englert
- Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85741 Garching, Germany
| | - Sascha W Epp
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Benjamin Erk
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Lutz Foucar
- Max-Planck-Institut für Medizinische Forschung, Jahnstrasse 29, 69120 Heidelberg, Germany
| | | | - Alexander Hexemer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Martin Huth
- PNSensor GmbH, Otto-Hahn-Ring 6, 81739 München, Germany
| | - Stephen R Leone
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jonathan H Ma
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Stefano Marchesini
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Daniel M Neumark
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Billy K Poon
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - James Prell
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Daniel Rolles
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Benedikt Rudek
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Artem Rudenko
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Martin Seifrid
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Michele Swiggers
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Joachim Ullrich
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Fabian Weise
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Petrus Zwart
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Christoph Bostedt
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Oliver Gessner
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Andrey F Vilesov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| |
Collapse
|
14
|
Blancafort-Jorquera M, González M. Vibrational energy relaxation of a diatomic molecule in a superfluid helium nanodroplet: influence of the nanodroplet size, interaction energy and energy gap. Phys Chem Chem Phys 2021; 23:25961-25973. [PMID: 34783338 DOI: 10.1039/d1cp03629g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The influence of the nanodroplet size, molecule-helium interaction potential energy and ν = 1 - ν = 0 vibrational energy gap on the vibrational energy relaxation (VER) of a diatomic molecule (X2) in a superfluid helium nanodroplet [HeND or (4He)N; finite quantum solvent at T = 0.37 K] has been studied using a hybrid quantum approach recently proposed by us and taking as a reference the VER results on the I2@(4He)100 doped nanodroplet (Vilà et al., Phys. Chem. Chem. Phys., 2018, 20, 118, which corresponds to the first theoretical study on the VER of molecules embedded in a HeND). This has allowed us to obtain a deeper insight into the vibrational relaxation dynamics. The nanodroplet size has a very small effect on the VER, as this process mainly depends on the interaction between the molecule and the nanodroplet first solvation shell. Regarding the interaction potential energy and the energy gap, both factors play an important and comparable role in the VER time properties (global relaxation time, lifetime and transition time). As the former becomes stronger the relaxation time properties decrease in a significant way (their inverse follows a linear dependence with respect to the ν = 1 - ν = 0 coupling term) and they also decrease in a significant manner when the energy gap diminishes (linear dependence on the ν = 1 - ν = 0 energy difference). We expect that this study will motivate further work on the vibrational relaxation process in HeNDs.
Collapse
Affiliation(s)
- Miquel Blancafort-Jorquera
- Departament de Ciència dels Materials i Química Física and IQTC, Universitat de Barcelona, Martí i Franquès, 1-11, 08028 Barcelona, Spain.
| | - Miguel González
- Departament de Ciència dels Materials i Química Física and IQTC, Universitat de Barcelona, Martí i Franquès, 1-11, 08028 Barcelona, Spain.
| |
Collapse
|
15
|
Raston PL. Laser spectroscopy of helium solvated molecules: probing the inertial response. Phys Chem Chem Phys 2021; 23:25467-25479. [PMID: 34761773 DOI: 10.1039/d1cp04368d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Helium is the only solvent within which molecules can "freely" rotate, albeit with an increased moment of inertia relative to the gas phase. Evidence for this can be obtained by performing infrared laser spectroscopy on molecules embedded large helium clusters (nanodroplets), which often reveals rotationally resolved lines that are more closely spaced than in vacuo. The additional rotational inertia results from coupling of the helium to the molecule (rotor), and decreases in going from heavy (e.g., SF6) to light (e.g., CH4) rotors due to a partial breakdown in the adiabatic (following) approximation; faster (lighter) rotors cannot couple as well to helium since their effective interaction with helium is less anisotropic. In addition to this "mass" dependence to the coupling, there is also a time dependence to it, which shows up in the IR spectra as an asymmetry in the rovibrational lineshapes; this results from a delay in the response of helium to the change in rotational speed of the solvated molecule (when ΔJ = ±1). In this perspective we discuss the coupling between various probe molecules and helium that have been investigated by infrared laser spectroscopy in the frequency domain.
Collapse
Affiliation(s)
- Paul L Raston
- Department of Chemistry, University of Adelaide, SA 5005, Australia.,Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia 22807, USA.
| |
Collapse
|
16
|
Abstract
A beam of size-selected charged helium droplets was crossed with an electron beam, and the ion efficiency curves for the product droplets in all different charge states were recorded. We estimate that the selected helium droplets on their passage through the electron beam are hit by several hundred electrons which can interact with the individual He atoms of the droplets. Reaction channels corresponding to the removal or capture of up to eight electrons were identified, and in all cases, inelastic scattering and the formation of metastable helium played a significant role.
Collapse
|
17
|
Bisset RN, Ardila LAP, Santos L. Quantum Droplets of Dipolar Mixtures. PHYSICAL REVIEW LETTERS 2021; 126:025301. [PMID: 33512237 DOI: 10.1103/physrevlett.126.025301] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/03/2020] [Indexed: 05/12/2023]
Abstract
Recently achieved two-component dipolar Bose-Einstein condensates open exciting possibilities for the study of mixtures of ultradilute quantum liquids. While nondipolar self-bound (without external confinement) mixtures are necessarily miscible with an approximately fixed ratio between the two densities, the density ratio for the dipolar case is free. Therefore, self-bound dipolar mixtures present qualitatively novel and much richer physics, characterized by three possible ground-state phases: miscible, symmetric immiscible, and asymmetric immiscible, which may in principle occur at any population imbalance. Self-bound immiscible droplets are possible due to mutual nonlocal intercomponent attraction, which results in the formation of a droplet molecule. Moreover, our analysis of the impurity regime shows that quantum fluctuations in the majority component crucially modify the miscibility of impurities. Our work opens intriguing perspectives for the exploration of spinor physics in ultradilute liquids, which should resemble to some extent that of ^{4}He-^{3}He droplets and impurity-doped helium droplets.
Collapse
Affiliation(s)
- R N Bisset
- Institut für Theoretische Physik, Leibniz Universität Hannover, Germany
- Institut für Experimentalphysik, Universität Innsbruck, Innsbruck, Austria
| | - L A Peña Ardila
- Institut für Theoretische Physik, Leibniz Universität Hannover, Germany
| | - L Santos
- Institut für Theoretische Physik, Leibniz Universität Hannover, Germany
| |
Collapse
|
18
|
Liang J, Kresin VV. Kinetic energy deposited into a nanodroplet, cluster, or molecule in a sticking collision with background gas. J Chem Phys 2020; 153:196101. [PMID: 33218223 DOI: 10.1063/5.0031865] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In processes when particles such as nanodroplets, clusters, or molecules move through a dilute background gas and undergo capture collisions, it is often important to know how much translational kinetic energy is deposited into the particles by these pick-up events. For sticking collisions with a Maxwell-Boltzmann gas, an exact expression is derived, which is valid for arbitrary relative magnitudes of the particle and thermal gas speeds.
Collapse
Affiliation(s)
- Jiahao Liang
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA
| | - Vitaly V Kresin
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA
| |
Collapse
|
19
|
Kelbg M, Zabel M, Krebs B, Kazak L, Meiwes-Broer KH, Tiggesbäumker J. Temporal Development of a Laser-Induced Helium Nanoplasma Measured through Auger Emission and Above-Threshold Ionization. PHYSICAL REVIEW LETTERS 2020; 125:093202. [PMID: 32915628 DOI: 10.1103/physrevlett.125.093202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 04/14/2020] [Accepted: 07/23/2020] [Indexed: 06/11/2023]
Abstract
Femtosecond pump-probe electron and ion spectroscopy is applied to study the development of a helium nanoplasma up to the nanosecond timescale. Electrons, bound by the deep confining mean-field potential, are elevated toward the vacuum level in the nanoplasma expansion. Subsequent electron recombination gives rise to transitions between He^{+} states, resulting in autoionization. The time-resolved analysis of the energy transfer to quasifree electrons reveals a transient depletion of the Auger emission, which allows for a temporal gate to map the distribution of delocalized electrons in the developing mean field. Furthermore, we trace the recombination of delocalized electrons near the vacuum level into highly excited Rydberg states. Transient above-threshold ionization is introduced as a diagnostic tool to resolve the dynamics. Thus, the development of the electron distribution in the nanoplasma mean-field potential can be monitored via the features observed in the emission spectra.
Collapse
Affiliation(s)
- M Kelbg
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany
| | - M Zabel
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany
| | - B Krebs
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany
| | - L Kazak
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany
| | - K-H Meiwes-Broer
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany and Department "Life, Light, and Matter," Universität Rostock, 18059 Rostock, Germany
| | - J Tiggesbäumker
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany and Department "Life, Light, and Matter," Universität Rostock, 18059 Rostock, Germany
| |
Collapse
|
20
|
González-Lezana T, Echt O, Gatchell M, Bartolomei M, Campos-Martínez J, Scheier P. Solvation of ions in helium. INT REV PHYS CHEM 2020. [DOI: 10.1080/0144235x.2020.1794585] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Tomás González-Lezana
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas IFF-CSIC, Madrid, Spain
| | - Olof Echt
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
- Department of Physics, University of New Hampshire, Durham, NH, USA
| | - Michael Gatchell
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - Massimiliano Bartolomei
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas IFF-CSIC, Madrid, Spain
| | - José Campos-Martínez
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas IFF-CSIC, Madrid, Spain
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
| |
Collapse
|
21
|
Tanyag RMP, Feinberg AJ, O’Connell SMO, Vilesov AF. Disintegration of diminutive liquid helium jets in vacuum. J Chem Phys 2020; 152:234306. [DOI: 10.1063/5.0004503] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Rico Mayro P. Tanyag
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Alexandra J. Feinberg
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Sean M. O. O’Connell
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Andrey F. Vilesov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, USA
| |
Collapse
|
22
|
Brieuc F, Schran C, Uhl F, Forbert H, Marx D. Converged quantum simulations of reactive solutes in superfluid helium: The Bochum perspective. J Chem Phys 2020; 152:210901. [DOI: 10.1063/5.0008309] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Fabien Brieuc
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Christoph Schran
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Felix Uhl
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Harald Forbert
- Center for Solvation Science ZEMOS, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| |
Collapse
|
23
|
García-Alfonso E, Coppens F, Barranco M, Pi M, Stienkemeier F, Halberstadt N. Alkali atoms attached to vortex-hosting helium nanodroplets. J Chem Phys 2020; 152:194109. [PMID: 33687233 DOI: 10.1063/5.0008923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Light absorption or fluorescence excitation spectroscopy of alkali atoms attached to 4He droplets is investigated as a possible way for detecting the presence of vortices. To this end, we have calculated the equilibrium configuration and energetics of alkali atoms attached to a 4He1000 droplet hosting a vortex line using 4He density functional theory. We use them to study how the dipole absorption spectrum of the alkali atom is modified when the impurity is attached to a vortex line. Spectra are found to be blue-shifted (higher frequencies) and broadened compared to vortex-free droplets because the dimple in which the alkali atom sits at the intersection of the vortex line and the droplet surface is deeper. This effect is smaller for lighter alkali atoms and all the more so when using a quantum description since, in this case, they sit further away from the droplet surface on average due to their zero-point motion. Spectral modifications due to the presence of a vortex line are minor for np ← ns excitation and therefore insufficient for vortex detection. In the case of higher n'p ← ns or n's ← ns (n' > n) excitations, the shifts are larger as the excited state orbital is more extended and therefore more sensitive to changes in the surrounding helium density.
Collapse
Affiliation(s)
| | - Francois Coppens
- Université Toulouse 3 and CNRS, Laboratoire des Collisions, Agrégats et Réactivité, IRSAMC, 118 route de Narbonne, F-31062 Toulouse Cedex 09, France
| | - Manuel Barranco
- Université Toulouse 3 and CNRS, Laboratoire des Collisions, Agrégats et Réactivité, IRSAMC, 118 route de Narbonne, F-31062 Toulouse Cedex 09, France
| | - Martí Pi
- Departament FQA, Facultat de Física, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain
| | | | - Nadine Halberstadt
- Université Toulouse 3 and CNRS, Laboratoire des Collisions, Agrégats et Réactivité, IRSAMC, 118 route de Narbonne, F-31062 Toulouse Cedex 09, France
| |
Collapse
|
24
|
Kranabetter L, Bersenkowitsch NK, Martini P, Gatchell M, Kuhn M, Laimer F, Schiller A, Beyer MK, Ončák M, Scheier P. Considerable matrix shift in the electronic transitions of helium-solvated cesium dimer cation Cs 2He. Phys Chem Chem Phys 2019; 21:25362-25368. [PMID: 31702748 PMCID: PMC7116336 DOI: 10.1039/c9cp04790e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
We investigate the photodissociation of helium-solvated cesium dimer cations using action spectroscopy and quantum chemical calculations. The spectrum of Cs2He+ shows three distinct absorption bands into both bound and dissociative states. Upon solvation with further helium atoms, considerable shifts of the absorption bands are observed, exceeding 0.1 eV (850 cm-1) already for Cs2He10+, along with significant broadening. The shifts are highly sensitive to the character of the excited state. Our calculations show that helium atoms adsorb on the ends of Cs2+. The shifts are particularly pronounced if the excited state orbitals extend to the area occupied by the helium atoms. In this case, Pauli repulsion leads to a deformation of the excited state orbitals, resulting in the observed blue shift of the transition. Since the position of the weakly bound helium atoms is ill defined, Pauli repulsion also explains the broadening.
Collapse
Affiliation(s)
- Lorenz Kranabetter
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Nina K Bersenkowitsch
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Paul Martini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Michael Gatchell
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria. and Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - Martin Kuhn
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Felix Laimer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Arne Schiller
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Martin K Beyer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Milan Ončák
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| |
Collapse
|
25
|
Blancafort-Jorquera M, Vilà A, González M. Quantum-classical approach to the reaction dynamics in a superfluid helium nanodroplet. The Ne 2 dimer and Ne-Ne adduct formation reaction Ne + Ne-doped nanodroplet. Phys Chem Chem Phys 2019; 21:24218-24231. [PMID: 31661098 DOI: 10.1039/c9cp04561a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dynamics of the Ne2 dimer and Ne-Ne adduct formation in a superfluid helium nanodroplet [(4He)N; T = 0.37 K], Ne + Ne@(4He)N→ Ne2@(4He)N'/Ne-Ne@(4He)N' + (N-N')4He with N = 500, has been investigated using a hybrid approach (quantum and classical mechanics (QM-CM) descriptions for helium and the Ne atoms, respectively) and taking into account the angular momentum of the attacking Ne atom, Ne(1). Comparison with zero angular momentum QM results of our own shows that the present results are similar to the quantum ones for the initial Ne(1) velocities (v0) of 500 and 800 m s-1 (the former one being the most probable velocity of Ne at 300 K), in all cases leading to the Ne2 dimer (re = 3.09 Å). However, significant differences appear below v0 = 500 m s-1, because in the QM-CM dynamics, instead of the dimer, a Ne-Ne adduct is formed (r0 = 5.45 Å). The formation of this adduct will probably dominate as the contribution to reactivity of angular momenta larger than zero is the leading one and angular momentum strongly acts against the Ne2 production. Angular momentum adds further difficulties in producing the dimer, since it makes it more difficult to remove the helium density between both Ne atoms to lead, subsequently, to the Ne2 molecule. Hence, the formation of the neon-neon adduct, Ne-Ne@(4He)N', clearly dominates the reactivity of the system, which results in the formation of a "quantum gel"/"quantum foam", because the two Ne atoms essentially maintain their identity inside the nanodroplet. Large enough Ne(1) initial angular momentum values can induce the formation of vortex lines by the collapse of superficial excitations (ripplons), but they occur with greater difficulty than in the case of the capture of the Ne atom by a non doped helium nanodroplet, due to the wave interferences induced by the Ne induced by the solvation layers of the Ne atom originally placed inside the nanodroplet. We hope that this work will encourage other researchers to investigate the reaction dynamics in helium nanodroplets, an interesting topic on which there are few studies available.
Collapse
Affiliation(s)
- Miquel Blancafort-Jorquera
- Departament de Ciència de Materials i Química Física and IQTC, Universitat de Barcelona, Martí i Franquès, 1-11, 08028 Barcelona, Spain.
| | | | | |
Collapse
|
26
|
Kazak L, Göde S, Meiwes-Broer KH, Tiggesbäumker J. Photoelectron Spectroscopy on Magnesium Ensembles in Helium Nanodroplets. J Phys Chem A 2019; 123:5951-5956. [DOI: 10.1021/acs.jpca.9b02880] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
27
|
Abstract
Free superfluid helium droplets constitute a versatile medium for a diverse range of experiments in physics and chemistry that extend from studies of the fundamental laws of superfluid motion to the synthesis of novel nanomaterials. In particular, the emergence of quantum vortices in rotating helium droplets is one of the most dramatic hallmarks of superfluidity and gives detailed access to the wave function describing the quantum liquid. This review provides an introduction to quantum vorticity in helium droplets, followed by a historical account of experiments on vortex visualization in bulk superfluid helium and a more detailed discussion of recent advances in the study of the rotational motion of isolated, nano- to micrometer-scale superfluid helium droplets. Ultrafast X-ray and extreme ultraviolet scattering techniques enabled by X-ray free-electron lasers and high-order harmonic generation in particular have facilitated the in situ detection of droplet shapes and the imaging of vortex structures inside individual, isolated droplets. New applications of helium droplets ranging from studies of quantum phase separations to mechanisms of low-temperature aggregation are discussed.
Collapse
Affiliation(s)
- Oliver Gessner
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Andrey F. Vilesov
- Department of Chemistry and Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, USA
| |
Collapse
|
28
|
Lasserus M, Knez D, Schnedlitz M, Hauser AW, Hofer F, Ernst WE. On the passivation of iron particles at the nanoscale. NANOSCALE ADVANCES 2019; 1:2276-2283. [PMID: 36131962 PMCID: PMC9418694 DOI: 10.1039/c9na00161a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 04/22/2019] [Indexed: 05/08/2023]
Abstract
The oxidation of Fe@Au core@shell clusters with sizes below 5 nm is studied via high resolution scanning transmission electron microscopy. The bimetallic nanoparticles are grown in superfluid helium droplets under fully inert conditions, avoiding any effect of solvents or template structures, and deposited on amorphous carbon. Oxidation resistivity is tested by exposure to oxygen at ambient conditions. The passivating effect of Au-shells is studied in detail and a critical Au shell thickness is determined which keeps the Fe core completely unharmed. Additionally, we present the first synthesis of Fe@Au@Fe-oxide onion-type structures.
Collapse
Affiliation(s)
- Maximilian Lasserus
- Institute of Experimental Physics, Graz University of Technology Petersgasse 16 A-8010 Graz Austria +43-316-873-108140 +43-316-873-8157 +43-316-873-8140
| | - Daniel Knez
- Institute for Electron Microscopy and Nanoanalysis & Graz Centre for Electron Microscopy, Graz University of Technology Steyrergasse 17 A-8010 Graz Austria
| | - Martin Schnedlitz
- Institute of Experimental Physics, Graz University of Technology Petersgasse 16 A-8010 Graz Austria +43-316-873-108140 +43-316-873-8157 +43-316-873-8140
| | - Andreas W Hauser
- Institute of Experimental Physics, Graz University of Technology Petersgasse 16 A-8010 Graz Austria +43-316-873-108140 +43-316-873-8157 +43-316-873-8140
| | - Ferdinand Hofer
- Institute for Electron Microscopy and Nanoanalysis & Graz Centre for Electron Microscopy, Graz University of Technology Steyrergasse 17 A-8010 Graz Austria
| | - Wolfgang E Ernst
- Institute of Experimental Physics, Graz University of Technology Petersgasse 16 A-8010 Graz Austria +43-316-873-108140 +43-316-873-8157 +43-316-873-8140
| |
Collapse
|
29
|
Kelbg M, Zabel M, Krebs B, Kazak L, Meiwes-Broer KH, Tiggesbäumker J. Auger emission from the Coulomb explosion of helium nanoplasmas. J Chem Phys 2019; 150:204302. [DOI: 10.1063/1.5089943] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M. Kelbg
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany
| | - M. Zabel
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany
| | - B. Krebs
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany
| | - L. Kazak
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany
| | - K.-H. Meiwes-Broer
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany
- Department of Life, Light and Matter, Universität Rostock, 18059 Rostock, Germany
| | - J. Tiggesbäumker
- Institut für Physik, Universität Rostock, 18059 Rostock, Germany
- Department of Life, Light and Matter, Universität Rostock, 18059 Rostock, Germany
| |
Collapse
|
30
|
Pérez de Tudela R, Martini P, Goulart M, Scheier P, Pirani F, Hernández-Rojas J, Bretón J, Ortiz de Zárate J, Bartolomei M, González-Lezana T, Hernández MI, Campos-Martínez J, Villarreal P. A combined experimental and theoretical investigation of Cs + ions solvated in He N clusters. J Chem Phys 2019; 150:154304. [PMID: 31005067 DOI: 10.1063/1.5092566] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Solvation of Cs+ ions inside helium droplets has been investigated both experimentally and theoretically. On the one hand, mass spectra of doped helium clusters ionized with a crossed electron beam, HeNCs+, have been recorded for sizes up to N = 60. The analysis of the ratio between the observed peaks for each size N reveals evidences of the closure of the first solvation shell when 17 He atoms surround the alkali ion. On the other hand, we have obtained energies and geometrical structures of the title clusters by means of basin-hopping, diffusion Monte Carlo (DMC), and path integral Monte Carlo (PIMC) methods. The analytical He-Cs+ interaction potential employed in our calculations is represented by the improved Lennard-Jones expression optimized on high level ab initio energies. The weakness of the existing interaction between helium and Cs+ in comparison with some other alkali ions such as Li+ is found to play a crucial role. Our theoretical findings confirm that the first solvation layer is completed at N = 17 and both evaporation and second difference energies obtained with the PIMC calculation seem to reproduce a feature observed at N = 12 for the experimental ion abundance. The analysis of the DMC probability distributions reveals the important contribution from the icosahedral structure to the overall configuration for He12Cs+.
Collapse
Affiliation(s)
| | - Paul Martini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Marcelo Goulart
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Universitá di Perugia, 06123 Perugia, Italy
| | - Javier Hernández-Rojas
- Departamento de Física and IUdEA, Universidad de La Laguna, La Laguna, 38205 Tenerife, Spain
| | - José Bretón
- Departamento de Física and IUdEA, Universidad de La Laguna, La Laguna, 38205 Tenerife, Spain
| | | | | | | | - Marta I Hernández
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, 28006 Madrid, Spain
| | | | - Pablo Villarreal
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, 28006 Madrid, Spain
| |
Collapse
|
31
|
Lasserus M, Schnedlitz M, Messner R, Lackner F, Ernst WE, Hauser AW. Vanadium(V) oxide clusters synthesized by sublimation from bulk under fully inert conditions. Chem Sci 2019; 10:3473-3480. [PMID: 30996937 PMCID: PMC6432649 DOI: 10.1039/c8sc05699d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 02/23/2019] [Indexed: 12/01/2022] Open
Abstract
While laser ablation in combination with electron impact mass spectroscopy yield numerous fragments and reaction products, helium-mediated mass analysis reveals the sublimation from bulk in units of (V2O5)2.
Oxide nanoparticles in the size range of a few nanometers are typically synthesized in solution or via laser ablation techniques, which open numerous channels for structural change via chemical reactions or fragmentation processes. In this work, neutral vanadium oxide nanoparticles are instead synthesized by sublimation from bulk in combination with a pickup by superfluid helium droplets. Mass spectroscopy measurements clearly demonstrate the preservation of the bulk stoichiometric ratio of vanadium to oxygen in He-grown nanoparticles, indicating a tendency towards tetrahedral coordination of the vanadium centers in finite geometries. This unexpected finding opens up new possibilities for a combined on-the-fly synthesis of nanoparticles consisting of metal and metal-oxide layers. In comparison to mass spectra obtained via direct ionization of vanadium oxide in an effusive beam, where strong fragmentation occurred, we observe a clear preference for (V2O5)n oligomers with even n inside the He nanodroplets, which is further investigated and explained using the electronic structure theory.
Collapse
Affiliation(s)
- Maximilian Lasserus
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; ; Tel: +43 316 873 8157 ; Tel: +43 316 873 8140
| | - Martin Schnedlitz
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; ; Tel: +43 316 873 8157 ; Tel: +43 316 873 8140
| | - Roman Messner
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; ; Tel: +43 316 873 8157 ; Tel: +43 316 873 8140
| | - Florian Lackner
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; ; Tel: +43 316 873 8157 ; Tel: +43 316 873 8140
| | - Wolfgang E Ernst
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; ; Tel: +43 316 873 8157 ; Tel: +43 316 873 8140
| | - Andreas W Hauser
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; ; Tel: +43 316 873 8157 ; Tel: +43 316 873 8140
| |
Collapse
|
32
|
Coppens F, Ancilotto F, Barranco M, Halberstadt N, Pi M. Dynamics of impurity clustering in superfluid 4He nanodroplets. Phys Chem Chem Phys 2019; 21:17423-17432. [DOI: 10.1039/c9cp02789k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Snapshot taken at 75 ps of the capture of six Ar atoms hitting a 4He5000 droplet at 100 m s−1.
Collapse
Affiliation(s)
- François Coppens
- Université Toulouse 3 and CNRS
- Laboratoire des Collisions
- Agrégats et Réactivité
- IRSAMC
- F-31062 Toulouse Cedex 09
| | - Francesco Ancilotto
- Dipartimento di Fisica e Astronomia “Galileo Galilei” and CNISM
- Università di Padova
- 35122 Padova
- Italy
- CNR-IOM Democritos
| | - Manuel Barranco
- Université Toulouse 3 and CNRS
- Laboratoire des Collisions
- Agrégats et Réactivité
- IRSAMC
- F-31062 Toulouse Cedex 09
| | - Nadine Halberstadt
- Université Toulouse 3 and CNRS
- Laboratoire des Collisions
- Agrégats et Réactivité
- IRSAMC
- F-31062 Toulouse Cedex 09
| | - Martí Pi
- Departament FQA
- Facultat de Física
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| |
Collapse
|
33
|
Kelbg M, Heidenreich A, Kazak L, Zabel M, Krebs B, Meiwes-Broer KH, Tiggesbäumker J. Comparison of Electron and Ion Emission from Xenon Cluster-Induced Ignition of Helium Nanodroplets. J Phys Chem A 2018; 122:8107-8113. [PMID: 30239204 DOI: 10.1021/acs.jpca.8b06673] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The charging dynamics of helium droplets driven by embedded xenon cluster ignition in strong laser fields is studied by comparing the abundances of helium and highly charged Xe ions to the electron signal. Femtosecond pump-probe experiments show that near the optimal delay for highly charged xenon the electron yield increases, especially at low energies. The electron signature can be traced back to the ionization of the helium environment by Xe seed electrons. Accompanying molecular dynamics simulations suggest a two-step ionization scenario in the Xe-He core-shell system. In contrast to xenon, the experimental signal of the helium ions, as well as low-energy electron emission show a deviating delay dependence, indicating differences in the temporal and spacial development of the charge state distribution of Xe core and He surrounding. From the pump-probe dependence of the electron emission, effective temperatures can be extracted, indicating the nanoplasma decay.
Collapse
Affiliation(s)
- Michael Kelbg
- Institute of Physics , University of Rostock , Rostock 18059 , Germany
| | - Andreas Heidenreich
- Kimika Fakultatea , Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC) , P.K. 1072, Donostia 20018 , Spain.,IKERBASQUE, Basque Foundation for Science , Bilbao 48013 , Spain
| | - Lev Kazak
- Institute of Physics , University of Rostock , Rostock 18059 , Germany
| | - Michael Zabel
- Institute of Physics , University of Rostock , Rostock 18059 , Germany
| | - Bennet Krebs
- Institute of Physics , University of Rostock , Rostock 18059 , Germany
| | - Karl-Heinz Meiwes-Broer
- Institute of Physics , University of Rostock , Rostock 18059 , Germany.,Department Life, Light and Matter , University of Rostock , Rostock 18059 , Germany
| | - Josef Tiggesbäumker
- Institute of Physics , University of Rostock , Rostock 18059 , Germany.,Department Life, Light and Matter , University of Rostock , Rostock 18059 , Germany
| |
Collapse
|
34
|
Nijjar P, Krylov AI, Prezhdo OV, Vilesov AF, Wittig C. Conversion of He(2 3 S) to He 2( a 3Σ u+) in Liquid Helium. J Phys Chem Lett 2018; 9:6017-6023. [PMID: 30272979 DOI: 10.1021/acs.jpclett.8b02454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The report of an anomalously intense He4+ peak in electron impact mass spectra of large helium droplets created a stir 3 decades ago that continues to this day. When the electron kinetic energy exceeds 41 eV, an additional pathway opens that yields He4+ predominantly in an electronically excited metastable state. A pair of He*(23 S) atoms has been implicated based on the isolated He* energy of 19.82 eV and the 41 eV threshold, and the creation of He4+ has been conjectured to proceed via a pair of He2*( a3Σ u+) precursors. The mechanism whereby He* converts to He2* in liquid helium has remained a mystery, however. High level ab initio theory combined with classical molecular dynamics has been applied to systems comprising small numbers of He atoms. The conversion of He* to He2* in such systems is shown to be due to a simple many-body effect that yields He2* rapidly and efficiently.
Collapse
Affiliation(s)
- P Nijjar
- Department of Chemistry , University of Southern California , 3620 McClintock Avenue , Los Angeles , California 90089-1062 , United States
| | - A I Krylov
- Department of Chemistry , University of Southern California , 3620 McClintock Avenue , Los Angeles , California 90089-1062 , United States
| | - O V Prezhdo
- Department of Chemistry , University of Southern California , 3620 McClintock Avenue , Los Angeles , California 90089-1062 , United States
| | - A F Vilesov
- Department of Chemistry , University of Southern California , 3620 McClintock Avenue , Los Angeles , California 90089-1062 , United States
| | - C Wittig
- Department of Chemistry , University of Southern California , 3620 McClintock Avenue , Los Angeles , California 90089-1062 , United States
| |
Collapse
|
35
|
Vindel Zandbergen P, Barranco M, Cargnoni F, Drabbels M, Pi M, Halberstadt N. Helium-induced electronic transitions in photo-excited Ba+–Hen exciplexes. J Chem Phys 2018; 148:144302. [DOI: 10.1063/1.5022863] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Patricia Vindel Zandbergen
- Laboratoire Collisions Agrégats Réactivité (LCAR), IRSAMC, Université de Toulouse, CNRS UMR 5589, Toulouse, France
| | - Manuel Barranco
- Laboratoire Collisions Agrégats Réactivité (LCAR), IRSAMC, Université de Toulouse, CNRS UMR 5589, Toulouse, France
- Departament FQA, Facultat de Física, Universitat de Barcelona, Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
| | | | - Marcel Drabbels
- Laboratory of Molecular Nanodynamics, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Martí Pi
- Departament FQA, Facultat de Física, Universitat de Barcelona, Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
| | - Nadine Halberstadt
- Laboratoire Collisions Agrégats Réactivité (LCAR), IRSAMC, Université de Toulouse, CNRS UMR 5589, Toulouse, France
| |
Collapse
|
36
|
Schnedlitz M, Lasserus M, Knez D, Hauser AW, Hofer F, Ernst WE. Thermally induced breakup of metallic nanowires: experiment and theory. Phys Chem Chem Phys 2018; 19:9402-9408. [PMID: 28327747 DOI: 10.1039/c7cp00463j] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We present time-resolved transmission electron microscopy studies of the degradation of Au, Ag, Cu and Ni nanowires deposited on a heated support. The wires are grown under fully inert conditions in superfluid helium droplets and deposited onto amorphous carbon. The inherent stability of these pristine metal nanowires with diameters below 10 nm is investigated in the absence of any stabilizers, templates or solvents. The phenomenon of Rayleigh-breakup, a consequence of diffusion processes along the wire surfaces, is analysed in situ via scans over time and support temperature. Our experimental efforts are combined with simulations based on a novel model featuring a cellular automaton to emulate surface diffusion. Based on this model, correlations between the material parameters and actual breakup behaviour are studied.
Collapse
Affiliation(s)
- Martin Schnedlitz
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
| | - Maximilian Lasserus
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
| | - Daniel Knez
- Institute for Electron Microscopy and Nanoanalysis & Graz Centre for Electron Microscopy, Graz University of Technology, Steyrergasse 17, A-8010 Graz, Austria
| | - Andreas W Hauser
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
| | - Ferdinand Hofer
- Institute for Electron Microscopy and Nanoanalysis & Graz Centre for Electron Microscopy, Graz University of Technology, Steyrergasse 17, A-8010 Graz, Austria
| | - Wolfgang E Ernst
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
| |
Collapse
|
37
|
|
38
|
Fine J, Verma D, Jones CF, Wittig C, Vilesov AF. Formation of He4+via electron impact of helium droplets. J Chem Phys 2018; 148:044302. [DOI: 10.1063/1.5001715] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jordan Fine
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Deepak Verma
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Curtis F. Jones
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Curt Wittig
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Andrey F. Vilesov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| |
Collapse
|
39
|
Lasserus M, Schnedlitz M, Knez D, Messner R, Schiffmann A, Lackner F, Hauser AW, Hofer F, Ernst WE. Thermally induced alloying processes in a bimetallic system at the nanoscale: AgAu sub-5 nm core-shell particles studied at atomic resolution. NANOSCALE 2018; 10:2017-2024. [PMID: 29319708 PMCID: PMC5795486 DOI: 10.1039/c7nr07286d] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/31/2017] [Indexed: 05/24/2023]
Abstract
Alloying processes in nanometre-sized Ag@Au and Au@Ag core@shell particles with average radii of 2 nm are studied via high resolution Transmission Electron Microscopy (TEM) imaging on in situ heatable carbon substrates. The bimetallic clusters are synthesized in small droplets of superfluid helium under fully inert conditions. After deposition, they are monitored during a heating cycle to 600 K and subsequent cooling. The core-shell structure, a sharply defined feature of the TEM High-Angle Annular Dark-Field images taken at room temperature, begins to blur with increasing temperature and transforms into a fully mixed alloy around 573 K. This transition is studied at atomic resolution, giving insights into the alloying process with unprecedented precision. A new image-processing method is presented, which allows a measurement of the temperature-dependent diffusion constant at the nanoscale. The first quantification of this property for a bimetallic structure <5 nm sheds light on the thermodynamics of finite systems and provides new input for current theoretical models derived from bulk data.
Collapse
Affiliation(s)
- Maximilian Lasserus
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| | - Martin Schnedlitz
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| | - Daniel Knez
- Institute for Electron Microscopy and Nanoanalysis & Graz Centre for Electron Microscopy , Graz University of Technology , Steyrergasse 17 , A-8010 Graz , Austria
| | - Roman Messner
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| | - Alexander Schiffmann
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| | - Florian Lackner
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| | - Andreas W. Hauser
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| | - Ferdinand Hofer
- Institute for Electron Microscopy and Nanoanalysis & Graz Centre for Electron Microscopy , Graz University of Technology , Steyrergasse 17 , A-8010 Graz , Austria
| | - Wolfgang E. Ernst
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| |
Collapse
|
40
|
Blancafort-Jorquera M, Vilà A, González M. Quantum-classical dynamics of the capture of neon atoms by superfluid helium nanodroplets. Phys Chem Chem Phys 2018; 20:29737-29753. [DOI: 10.1039/c8cp05140b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The capture dynamics of Ne by a HeND was studied theoretically in a detailed manner (energy and angular momentum transfer and vortex formation).
Collapse
Affiliation(s)
| | - Arnau Vilà
- Departament de Ciència de Materials i Química Física and IQTC
- Universitat de Barcelona
- Barcelona
- Spain
| | - Miguel González
- Departament de Ciència de Materials i Química Física and IQTC
- Universitat de Barcelona
- Barcelona
- Spain
| |
Collapse
|
41
|
Vilà A, Paniagua M, González M. Vibrational energy relaxation dynamics of diatomic molecules inside superfluid helium nanodroplets. The case of the I2 molecule. Phys Chem Chem Phys 2018; 20:118-130. [DOI: 10.1039/c7cp05694j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The vibrational relaxation (VER) of a X2 molecule in a 4He superfluid nanodroplet (HeND; 0.37 K) was studied adapting a quantum approach recently proposed by us. In the first theoretical study on the VER of molecules inside HeND the I2 molecule was examined [cascade mechanism (ν → ν − 1; ν − 1 → ν − 2; …) and time scale of ns].
Collapse
Affiliation(s)
- Arnau Vilà
- Departament de Ciència de Materials i Química Física and IQTC
- Universitat de Barcelona
- 08028 Barcelona
- Spain
- Departamento de Química Física Aplicada
| | - Miguel Paniagua
- Departamento de Química Física Aplicada
- Universidad Autónoma de Madrid
- 28049 Cantoblanco
- Spain
| | - Miguel González
- Departament de Ciència de Materials i Química Física and IQTC
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| |
Collapse
|
42
|
Ancilotto F, Barranco M, Coppens F, Eloranta J, Halberstadt N, Hernando A, Mateo D, Pi M. Density functional theory of doped superfluid liquid helium and nanodroplets. INT REV PHYS CHEM 2017. [DOI: 10.1080/0144235x.2017.1351672] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Francesco Ancilotto
- Dipartimento di Fisica e Astronomia ‘Galileo Galilei’ and CNISM, Università di Padova, Padova, Italy
- CNR-IOM Democritos, Trieste, Italy
| | - Manuel Barranco
- Facultat de Física, Departament FQA, Universitat de Barcelona, Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
- Laboratoire des Collisions, Agrégats et Réactivité, IRSAMC, Université Toulouse 3 and CNRS, Toulouse Cedex 09, France
| | - François Coppens
- Laboratoire des Collisions, Agrégats et Réactivité, IRSAMC, Université Toulouse 3 and CNRS, Toulouse Cedex 09, France
| | - Jussi Eloranta
- Department of Chemistry and Biochemistry, California State University at Northridge, Northridge, CA, USA
| | - Nadine Halberstadt
- Laboratoire des Collisions, Agrégats et Réactivité, IRSAMC, Université Toulouse 3 and CNRS, Toulouse Cedex 09, France
| | - Alberto Hernando
- Social Thermodynamics Applied Research (SThAR), EPFL Innovation Park, Lausanne, Switzerland
| | - David Mateo
- Applied Complexity Group, Singapore University of Technology and Design, Singapore, Singapore
| | - Martí Pi
- Facultat de Física, Departament FQA, Universitat de Barcelona, Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
| |
Collapse
|
43
|
Pototschnig JV, Lackner F, Hauser AW, Ernst WE. Rydberg states of alkali atoms on superfluid helium nanodroplets: inside or outside? Phys Chem Chem Phys 2017; 19:14718-14728. [PMID: 28540939 PMCID: PMC5708348 DOI: 10.1039/c7cp02332d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 05/12/2017] [Indexed: 11/28/2022]
Abstract
Electronic excitations of an electron bound to an alkali metal ion inside a droplet of superfluid 4He are computed via a combination of helium density functional theory and the numerical integration of the Schrödinger equation for a single electron in a modified, He density dependent atomic pseudopotential. The application of a spectral method to the radial part of the valence electron wavefunction allows the computation of highly excited Rydberg states. For low principal quantum numbers, the energy required to push the electron outward is larger than the solvation energy of the ion. However, for higher principal quantum numbers the situation is reversed, which suggests the stability of a system where the ion sits inside the droplet while the valence electron orbits the nanodroplet.
Collapse
Affiliation(s)
- Johann V. Pototschnig
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ;
| | - Florian Lackner
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ;
| | - Andreas W. Hauser
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ;
| | - Wolfgang E. Ernst
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ;
| |
Collapse
|
44
|
He Y, Zhang J, Lei L, Kong W. Self-Assembly of Iodine in Superfluid Helium Droplets: Halogen Bonds and Nanocrystals. Angew Chem Int Ed Engl 2017; 56:3541-3545. [PMID: 28220998 DOI: 10.1002/anie.201611922] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/18/2017] [Indexed: 11/09/2022]
Abstract
We present evidence of halogen bond in iodine clusters formed in superfluid helium droplets based on results from electron diffraction. Iodine crystals are known to form layered structures with intralayer halogen bonds, with interatomic distances shorter than the sum of the van der Waals radii of the two neighboring atoms. The diffraction profile of dimer dominated clusters embedded in helium droplets reveals an interatomic distance of 3.65 Å, much closer to the value of 3.5 Å in iodine crystals than to the van der Waals distance of 4.3 Å. The profile from larger iodine clusters deviates from a single layer structure; instead, a bi-layer structure qualitatively fits the experimental data. This work highlights the possibility of small halogen bonded iodine clusters, albeit in a perhaps limited environment of superfluid helium droplets. The role of superfluid helium in guiding the trapped molecules into local potential minima awaits further investigation.
Collapse
Affiliation(s)
- Yunteng He
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331, USA
| | - Jie Zhang
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331, USA
| | - Lei Lei
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331, USA
| | - Wei Kong
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331, USA
| |
Collapse
|
45
|
He Y, Zhang J, Lei L, Kong W. Self‐Assembly of Iodine in Superfluid Helium Droplets: Halogen Bonds and Nanocrystals. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611922] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yunteng He
- Department of Chemistry Oregon State University Corvallis OR 97331 USA
| | - Jie Zhang
- Department of Chemistry Oregon State University Corvallis OR 97331 USA
| | - Lei Lei
- Department of Chemistry Oregon State University Corvallis OR 97331 USA
| | - Wei Kong
- Department of Chemistry Oregon State University Corvallis OR 97331 USA
| |
Collapse
|
46
|
Renzler M, Daxner M, Kranabetter L, Kaiser A, Hauser AW, Ernst WE, Lindinger A, Zillich R, Scheier P, Ellis AM. Communication: Dopant-induced solvation of alkalis in liquid helium nanodroplets. J Chem Phys 2017; 145:181101. [PMID: 27846692 DOI: 10.1063/1.4967405] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Alkali metal atoms and small alkali clusters are classic heliophobes and when in contact with liquid helium they reside in a dimple on the surface. Here we show that alkalis can be induced to submerge into liquid helium when a highly polarizable co-solute, C60, is added to a helium nanodroplet. Evidence is presented that shows that all sodium clusters, and probably single Na atoms, enter the helium droplet in the presence of C60. Even clusters of cesium, an extreme heliophobe, dissolve in liquid helium when C60 is added. The sole exception is atomic Cs, which remains at the surface.
Collapse
Affiliation(s)
- Michael Renzler
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Matthias Daxner
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Lorenz Kranabetter
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Alexander Kaiser
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Andreas W Hauser
- Institut für Experimentalphysik, Technische Universität Graz, Petergasse 16, A-8010 Graz, Austria
| | - Wolfgang E Ernst
- Institut für Experimentalphysik, Technische Universität Graz, Petergasse 16, A-8010 Graz, Austria
| | - Albrecht Lindinger
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Robert Zillich
- Institut für Theoretische Physik, Johannes Kepler Universität, A-4040 Linz, Austria
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Andrew M Ellis
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| |
Collapse
|
47
|
von Vangerow J, Coppens F, Leal A, Pi M, Barranco M, Halberstadt N, Stienkemeier F, Mudrich M. Imaging Excited-State Dynamics of Doped He Nanodroplets in Real-Time. J Phys Chem Lett 2017; 8:307-312. [PMID: 27996261 DOI: 10.1021/acs.jpclett.6b02598] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The real-time dynamics of excited alkali metal atoms (Rb) attached to quantum fluid He nanodroplets is investigated using femtosecond imaging spectroscopy and time-dependent density functional theory. We disentangle the competing dynamics of desorption of excited Rb atoms off the He droplet surface and solvation inside the droplet interior as the Rb atom is ionized. For Rb excited to the 5p and 6p states, desorption occurs on starkly differing time scales (∼100 versus ∼1 ps, respectively). The comparison between theory and experiment indicates that desorption proceeds either impulsively (6p) or in a transition regime between impulsive dissociation and complex desorption (5p).
Collapse
Affiliation(s)
- Johannes von Vangerow
- Physikalisches Institut, Universität Freiburg , Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - François Coppens
- Laboratoire des Collisions, Agrégats, Réactivité, IRSAMC, UMR 5589, CNRS et Université Paul Sabatier-Toulouse 3, 118 route de Narbonne, F-31062 Toulouse Cedex 09, France
| | - Antonio Leal
- Departament FQA, Facultat de Física, and IN2UB, Universitat de Barcelona , Diagonal 645, 08028 Barcelona, Spain
| | - Martí Pi
- Departament FQA, Facultat de Física, and IN2UB, Universitat de Barcelona , Diagonal 645, 08028 Barcelona, Spain
| | - Manuel Barranco
- Laboratoire des Collisions, Agrégats, Réactivité, IRSAMC, UMR 5589, CNRS et Université Paul Sabatier-Toulouse 3, 118 route de Narbonne, F-31062 Toulouse Cedex 09, France
- Departament FQA, Facultat de Física, and IN2UB, Universitat de Barcelona , Diagonal 645, 08028 Barcelona, Spain
| | - Nadine Halberstadt
- Laboratoire des Collisions, Agrégats, Réactivité, IRSAMC, UMR 5589, CNRS et Université Paul Sabatier-Toulouse 3, 118 route de Narbonne, F-31062 Toulouse Cedex 09, France
| | - Frank Stienkemeier
- Physikalisches Institut, Universität Freiburg , Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Marcel Mudrich
- Physikalisches Institut, Universität Freiburg , Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| |
Collapse
|
48
|
Hauser AW, de Lara-Castells MP. Spatial quenching of a molecular charge-transfer process in a quantum fluid: the Cs x-C 60 reaction in superfluid helium nanodroplets. Phys Chem Chem Phys 2017; 19:1342-1351. [PMID: 27975088 DOI: 10.1039/c6cp06858h] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A recent experimental study [Renzler et al., J. Chem. Phys., 2016, 145, 181101] on superfluid helium nanodroplets reported different reactivities for Cs atoms and Cs2 dimers with C60 fullerenes inside helium droplets. Alkali metal atoms and clusters are heliophobic, therefore typically residing on the droplet surface, while fullerenes are fully immersed into the droplet. In this theoretical study, which combines standard methods of computational chemistry with orbital-free helium density functional theory, we show that the experimental findings can be interpreted in the light of a quenched electron-transfer reaction between the fullerene and the alkali dopant, which is additionally hindered by a reaction barrier stemming from the necessary extrusion of helium upon approach of the two reactants.
Collapse
Affiliation(s)
- Andreas W Hauser
- Graz University of Technology, Institute of Experimental Physics, Petersgasse 16, 8010 Graz, Austria.
| | | |
Collapse
|
49
|
Seki Y, Takayanagi T, Shiga M. Photoexcited Ag ejection from a low-temperature He cluster: a simulation study by nonadiabatic Ehrenfest ring-polymer molecular dynamics. Phys Chem Chem Phys 2017; 19:13798-13806. [DOI: 10.1039/c7cp00888k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nonadiabatic ring-polymer molecular dynamics simulations were performed to understand the photoexcitation dynamics of a low-temperature Ag·He500 cluster.
Collapse
Affiliation(s)
- Yusuke Seki
- Department of Chemistry
- Saitama University
- Saitama City
- Japan
| | | | - Motoyuki Shiga
- Center for Computational Science and E-Systems
- Japan Atomic Energy Agency
- Kashiwa
- Japan
| |
Collapse
|
50
|
Coppens F, Ancilotto F, Barranco M, Halberstadt N, Pi M. Capture of Xe and Ar atoms by quantized vortices in4He nanodroplets. Phys Chem Chem Phys 2017; 19:24805-24818. [DOI: 10.1039/c7cp03307a] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a computational study, based on time-dependent Density Functional theory, of the real-time interaction and trapping of Ar and Xe atoms in superfluid4He nanodroplets either pure or hosting quantized vortex lines.
Collapse
Affiliation(s)
- François Coppens
- Université de Toulouse
- UPS
- Laboratoire Collisions Agrégats Réactivité
- IRSAMC
- F-31062 Toulouse
| | - Francesco Ancilotto
- Dipartimento di Fisica e Astronomia ‘Galileo Galilei’ and CNISM
- Università di Padova
- 35122 Padova
- Italy
- CNR-IOM Democritos
| | - Manuel Barranco
- Université de Toulouse
- UPS
- Laboratoire Collisions Agrégats Réactivité
- IRSAMC
- F-31062 Toulouse
| | - Nadine Halberstadt
- Université de Toulouse
- UPS
- Laboratoire Collisions Agrégats Réactivité
- IRSAMC
- F-31062 Toulouse
| | - Martí Pi
- Facultat de Física
- Departament FQA
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| |
Collapse
|