1
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Kranabetter L, Kristensen HH, Schouder CA, Stapelfeldt H. Structure determination of alkali trimers on helium nanodroplets through laser-induced Coulomb explosion. J Chem Phys 2024; 160:131101. [PMID: 38557840 DOI: 10.1063/5.0200389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 03/15/2024] [Indexed: 04/04/2024] Open
Abstract
Alkali trimers, Ak3, located on the surface of He nanodroplets are triply ionized following multiphoton absorption from an intense femtosecond laser pulse, leading to fragmentation into three correlated Ak+ ions. Combining the information from threefold covariance analysis of the emission direction of the fragment ions and their kinetic energy distributions P(Ekin), we find that Na3, K3, and Rb3 have an equilateral triangular structure, corresponding to that of the lowest lying quartet state A2'4, and determine the equilibrium bond distance Req(Na3) = 4.65 ± 0.15 Å, Req(K3) = 5.03 ± 0.18 Å, and Req(Rb3) = 5.45 ± 0.22 Å. For K3 and Rb3, these values agree well with existing theoretical calculations, while for Na3, the value is 0.2-0.3 Å larger than the existing theoretical results. The discrepancy is ascribed to a minor internuclear motion of Na3 during the ionization process. In addition, we determine the distribution of internuclear distances P(R) under the assumption of fixed bond angles. The results are compared to the square of the internuclear wave function |Ψ(R)|2.
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Affiliation(s)
- Lorenz Kranabetter
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Henrik H Kristensen
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Constant A Schouder
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
- LIDYL, CNRS, CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Henrik Stapelfeldt
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
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2
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Kranabetter L, Kristensen HH, Ghazaryan A, Schouder CA, Chatterley AS, Janssen P, Jensen F, Zillich RE, Lemeshko M, Stapelfeldt H. Nonadiabatic Laser-Induced Alignment Dynamics of Molecules on a Surface. PHYSICAL REVIEW LETTERS 2023; 131:053201. [PMID: 37595218 DOI: 10.1103/physrevlett.131.053201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 07/08/2023] [Indexed: 08/20/2023]
Abstract
We demonstrate that a sodium dimer, Na_{2}(1^{3}Σ_{u}^{+}), residing on the surface of a helium nanodroplet, can be set into rotation by a nonresonant 1.0 ps infrared laser pulse. The time-dependent degree of alignment measured, exhibits a periodic, gradually decreasing structure that deviates qualitatively from that expected for gas-phase dimers. Comparison to alignment dynamics calculated from the time-dependent rotational Schrödinger equation shows that the deviation is due to the alignment dependent interaction between the dimer and the droplet surface. This interaction confines the dimer to the tangential plane of the droplet surface at the point where it resides and is the reason that the observed alignment dynamics is also well described by a 2D quantum rotor model.
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Affiliation(s)
- Lorenz Kranabetter
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Henrik H Kristensen
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Areg Ghazaryan
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Constant A Schouder
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
- Université Paris-Saclay, CEA, CNRS, LIDYL, 91191 Gif-sur-Yvette, France
| | - Adam S Chatterley
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Paul Janssen
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Frank Jensen
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Robert E Zillich
- Institute for Theoretical Physics, Johannes Kepler Universität Linz, Altenbergerstraße 69, A-4040 Linz, Austria
| | - Mikhail Lemeshko
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Henrik Stapelfeldt
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
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3
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von Haeften K, Laarmann T, Wabnitz H, Möller T. Relaxation dynamics of 3He and 4He clusters and droplets studied using near infrared and visible fluorescence excitation spectroscopy. Phys Chem Chem Phys 2023; 25:1863-1880. [PMID: 36541224 DOI: 10.1039/d2cp04594j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The relaxation dynamics of electronically excited 3He and 4He clusters and droplets is investigated using time-correlated near-infrared and visible (NIR/VIS) fluorescence excitation spectroscopy. A rich data set spanning a wide range of cluster and droplet sizes is produced. The spectral features broadly follow the vacuum ultraviolet excitation (VUV) spectra. However, when the NIR/VIS spectra are normalised to the VUV fluorescence, regions with distinctly different cluster size and isotope dependence are identified, enabling deeper insight into the relaxation mechanism. Particle density, location of atomic-like states and their principal quantum number, n, are found to play an important role in the relaxation. For states with n = 3 and higher, only energy within the surface region is transferred to excited atoms which are subsequently ejected from the surface and fluoresce in vacuum. For states with n = 2, energy from the entire region within clusters and droplets is transferred to the surface, leading to the ejection of excited atoms and excimers. Here, the energy is transferred by excitation hopping, which competes with radiative and non-radiative decay, making ejection and NIR/VIS fluorescence inefficient in increasingly larger droplets.
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4
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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.
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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
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5
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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.
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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.
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6
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Kristensen HH, Kranabetter L, Schouder CA, Stapper C, Arlt J, Mudrich M, Stapelfeldt H. Quantum-State-Sensitive Detection of Alkali Dimers on Helium Nanodroplets by Laser-Induced Coulomb Explosion. PHYSICAL REVIEW LETTERS 2022; 128:093201. [PMID: 35302820 DOI: 10.1103/physrevlett.128.093201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/21/2022] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
Rubidium dimers residing on the surface of He nanodroplets are doubly ionized by an intense femtosecond laser pulse leading to fragmentation into a pair of Rb^{+} ions. We show that the kinetic energy of the Rb^{+} fragment ions can be used to identify dimers formed in either the X ^{1}Σ_{g}^{+} ground state or in the lowest-lying triplet state, a ^{3}Σ_{u}^{+}. From the experiment, we estimate the abundance ratio of dimers in the a and X states as a function of the mean droplet size and find values between 4∶1 and 5∶1. Our technique applies generally to dimers and trimers of alkali atoms, here also demonstrated for Li_{2}, Na_{2}, and K_{2}, and will enable femtosecond time-resolved measurements of their rotational and vibrational dynamics, possibly with atomic structural resolution.
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Affiliation(s)
- Henrik H Kristensen
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Lorenz Kranabetter
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Constant A Schouder
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Christoph Stapper
- Faculty of Chemistry and Pharmacy, University of Würzburg, Am Hubland, Campus Süd, D-97074 Würzburg, Germany
| | - Jacqueline Arlt
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Marcel Mudrich
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Henrik Stapelfeldt
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
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7
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A Path Integral Molecular Dynamics Simulation of a Harpoon-Type Redox Reaction in a Helium Nanodroplet. Molecules 2021; 26:molecules26195783. [PMID: 34641327 PMCID: PMC8510490 DOI: 10.3390/molecules26195783] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 09/14/2021] [Accepted: 09/21/2021] [Indexed: 11/17/2022] Open
Abstract
We present path integral molecular dynamics (PIMD) calculations of an electron transfer from a heliophobic Cs2 dimer in its (3Σu) state, located on the surface of a He droplet, to a heliophilic, fully immersed C60 molecule. Supported by electron ionization mass spectroscopy measurements (Renzler et al., J. Chem. Phys.2016, 145, 181101), this spatially quenched reaction was characterized as a harpoon-type or long-range electron transfer in a previous high-level ab initio study (de Lara-Castells et al., J. Phys. Chem. Lett.2017, 8, 4284). To go beyond the static approach, classical and quantum PIMD simulations are performed at 2 K, slightly below the critical temperature for helium superfluidity (2.172 K). Calculations are executed in the NVT ensemble as well as the NVE ensemble to provide insights into real-time dynamics. A droplet size of 2090 atoms is assumed to study the impact of spatial hindrance on reactivity. By changing the number of beads in the PIMD simulations, the impact of quantization can be studied in greater detail and without an implicit assumption of superfluidity. We find that the reaction probability increases with higher levels of quantization. Our findings confirm earlier, static predictions of a rotational motion of the Cs2 dimer upon reacting with the fullerene, involving a substantial displacement of helium. However, it also raises the new question of whether the interacting species are driven out-of-equilibrium after impurity uptake, since reactivity is strongly quenched if a full thermal equilibration is assumed. More generally, our work points towards a novel mechanism for long-range electron transfer through an interplay between nuclear quantum delocalization within the confining medium and delocalized electronic dispersion forces acting on the two reactants.
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8
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Solvation of lithium ion in helium clusters: Structural properties and relative stabilities. J Mol Graph Model 2020; 98:107582. [PMID: 32200277 DOI: 10.1016/j.jmgm.2020.107582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/06/2020] [Accepted: 03/09/2020] [Indexed: 01/18/2023]
Abstract
Structural study and relative stabilities of Li+-doped helium clusters Li+Hen (n = 1-18) has been reported in this work using two theoretical protocols. The first one is based on the basin-hopping optimization technique, where the total energy of each cluster is described by an additive model describing Li+-He and He-He interactions. The second one is the DFT calculations, in which the initial structures are generated by ABCluster algorithm and CALYPSO software. The CSA shape was found where the first solvation shell is completed at n = 10. The relative stabilities of Li+Hen (n = 1-18) clusters have been discussed based on the variation of the binding energy, second-order difference in energy, fragmentation energy and HOMO-LUMO energy gap as a function of the cluster size. The results showed that Li+He10 is the most stable cluster. The dipole moment is calculated and showed the polar character of the Li+Hen clusters. Finally, the interatomic interactions have been examined topologically by the means of AIM and non-covalent reduced density gradient (NC-RDG) analyses.
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9
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Makrides C, Barker DS, Fedchak JA, Scherschligt J, Eckel S, Tiesinga E. Collisions of room-temperature helium with ultracold lithium and the van der Waals bound state of HeLi. PHYSICAL REVIEW. A 2020; 101:10.1103/PhysRevA.101.012702. [PMID: 33283081 PMCID: PMC7713563 DOI: 10.1103/physreva.101.012702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We have computed the thermally averaged total, elastic rate coefficient for the collision of a room-temperature helium atom with an ultracold lithium atom. This rate coefficient has been computed as part of the characterization of a cold-atom vacuum sensor based on laser-cooled 6Li or 7Li atoms that will operate in the ultrahigh-vacuum (p < 10-6 Pa) and extreme-high-vacuum (p < 10-10 Pa) regimes. The analysis involves computing the X 2 Σ+ HeLi Born-Oppenheimer potential followed by the numerical solution of the relevant radial Schrodinger equation. The potential is computed using a single-reference-coupled-cluster electronic-structure method with basis sets of different completeness in order to characterize our uncertainty budget. We predict that the rate coefficient for a 300 K helium gas and a 1 μK Li gas is 1.467(13) × 10-9 cm3/s for 4He + 6Li and 1.471(13) × 10-9 cm3/s for 4He + 7Li, where the numbers in parentheses are the one-standard-deviation uncertainties in the last two significant digits. We quantify the temperature dependence as well. Finally, we evaluate the s-wave scattering length and binding of the single van der Waals bound state of HeLi. We predict that this weakly bound level has a binding energy of -0.0064(43) × hc cm-1 and -0.0122(67) × hc cm-1 for 4He6Li and 4He7Li, respectively. The calculated binding energy of 4He7Li is consistent with the sole experimental determination.
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Affiliation(s)
- Constantinos Makrides
- Joint Quantum Institute, College Park, Maryland 20742, USA, and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Daniel S Barker
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - James A Fedchak
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Julia Scherschligt
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Stephen Eckel
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Eite Tiesinga
- Joint Quantum Institute, College Park, Maryland 20742, USA; Joint Center for Quantum Information and Computer Science, College Park, Maryland 20742, USA; and National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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10
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Ghosh A, Cederbaum LS, Gokhberg K. Electron transfer mediated decay in HeLi 2 cluster: Potential energy surfaces and decay widths. J Chem Phys 2019; 150:164309. [PMID: 31042888 DOI: 10.1063/1.5082952] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Electron transfer mediated decay (ETMD) is a process responsible for double ionization of dopants in He droplets. It is initiated by producing He+ in the droplet, which is neutralized by ETMD, and has been shown to strongly enhance the dopant's double ionization cross section. The efficiency of ETMD, the spectra of emitted secondary electrons, and the character of the ionic products depend on the nuclear dynamics during the decay. To date, there has been no theoretical investigation of multimode dynamics which accompanies ETMD, which could help to understand such dynamics in a He droplet. In this article, we consider the He-Li2 cluster where an ab initio examination of multimode dynamics during the electronic decay is feasible. Moreover, this cluster can serve as a minimal model for Li2 adsorbed on the droplet's surface-a system where ETMD can be observed experimentally. In He droplets, Li2 can be formed in both the ground X1Σg + and the first excited a3Σu + states. In this article, we present ab initio potential energy surfaces of the electronic states of the He-Li2 cluster involved in ETMD, as well as the respective decay widths. We show that the structure of these surfaces and expected nuclear dynamics strongly depend on the electronic state of Li2. Thus, the overall decay rate and the appearance of the observable electron spectra will be dictated by the electronic structure of the dopant.
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Affiliation(s)
- Aryya Ghosh
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
| | - Lorenz S Cederbaum
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
| | - Kirill Gokhberg
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
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11
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Dehdashti-Jahromi M, Farrokhpour H. Effect of helium nanoclusters on the spectroscopic properties of embedded SF 6: Ionization, excitation and vibration. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 173:772-782. [PMID: 27794241 DOI: 10.1016/j.saa.2016.10.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 06/06/2023]
Abstract
Ionization and excitation energies, IR and Raman spectra of sulfur hexafluoride (SF6), located inside helium (He) nanoclusters with different sizes (SF6@Hen; n=20, 40, 60), were calculated. The effect of the cluster size on the spectroscopic properties of the SF6 was investigated and found that the Hen-SF6 interaction in the He clusters with large number of atoms is small so that the ionization and absorption energies of SF6 are not affected while for small He nanoclusters the Hen-SF6 interaction is more important. The effect of Hen-SF6 interaction and deformation of the fragments on the photoelectron and absorption spectra of SF6@Hen were separated theoretically and discussed in details. It was deduced that the effect of the cluster size on the IR and Raman vibrational frequencies of the SF6 is negligible for the cluster size range considered in this work. Density functional theory (DFT) employing M06-2X functional and 6-31+G(df) basis set were used for optimizing the structures of SF6@Hen. Symmetry adapted cluster-configuration interaction (SAC-CI) methodology, with the same basis set, were used to calculate the ionization and excitation energies of the SF6@Hen structures. Using the calculated ionization and absorption energies and their intensities, the photoelectron and absorption spectra of the considered SF6@Hen structures were simulated and compared with the experiment.
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Affiliation(s)
- M Dehdashti-Jahromi
- Department of Chemistry, Isfahan University of Technology, Isfahan, Iran, 84156-83111
| | - H Farrokhpour
- Department of Chemistry, Isfahan University of Technology, Isfahan, Iran, 84156-83111.
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12
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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).
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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
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13
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Sieg A, von Vangerow J, Stienkemeier F, Dulieu O, Mudrich M. Desorption Dynamics of Rb 2 Molecules Off the Surface of Helium Nanodroplets. J Phys Chem A 2016; 120:7641-7649. [PMID: 27606714 DOI: 10.1021/acs.jpca.6b05732] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The desorption dynamics of rubidium dimers (Rb2) off the surface of helium nanodroplets induced by laser excitation is studied by employing both nanosecond and femtosecond ion imaging spectroscopy. Similarly to alkali metal atoms, we find that the Rb2 desorption process resembles the dissociation of a diatomic molecule. However, both angular and energy distributions of detected Rb2+ ions appear to be most crucially determined by the Rb2 intramolecular degrees of freedom rather than by those of the Rb2HeN complex. The pump-probe dynamics of Rb2+ is found to be slower than that of Rb+, pointing at a weaker effective guest-host repulsion for excited molecules than for single atoms.
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Affiliation(s)
- A Sieg
- Physikalisches Institut, Universität Freiburg , 79104 Freiburg, Germany
| | - J von Vangerow
- Physikalisches Institut, Universität Freiburg , 79104 Freiburg, Germany
| | - F Stienkemeier
- Physikalisches Institut, Universität Freiburg , 79104 Freiburg, Germany
| | - O Dulieu
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay , 91405 Orsay Cedex, France
| | - M Mudrich
- Physikalisches Institut, Universität Freiburg , 79104 Freiburg, Germany
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14
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Saidi S, Berriche H, Halberstadt N. Dissociative Photoionization of He···Li 2: A Theoretical Study. J Phys Chem A 2015; 119:11963-72. [DOI: 10.1021/acs.jpca.5b02428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Samah Saidi
- LCAR-IRSAMC, Université Toulouse 3 - Paul Sabatier and CNRS, 31062 Toulouse, France
- Laboratoire des
Interfaces et Matériaux Avancés, Département
de Physique, Faculté des Sciences, Université de Monastir, Avenue de l’Environnement, 5019 Monastir, Tunisia
| | - Hamid Berriche
- Laboratoire des
Interfaces et Matériaux Avancés, Département
de Physique, Faculté des Sciences, Université de Monastir, Avenue de l’Environnement, 5019 Monastir, Tunisia
- Department
of Mathematics and Natural Sciences, School of Arts and
Sciences, American University of Ras Al Khaimah, Ras Al Khaimah, UAE
| | - Nadine Halberstadt
- LCAR-IRSAMC, Université Toulouse 3 - Paul Sabatier and CNRS, 31062 Toulouse, France
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15
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Rodríguez-Cantano R, González-Lezana T, Prosmiti R, Delgado-Barrio G, Villarreal P, Jellinek J. Reactive scattering calculations for (87)Rb+(87)RbHe→Rb2((3)Σ(u)(+),v)+He from ultralow to intermediate energies. J Chem Phys 2015; 142:164304. [PMID: 25933761 DOI: 10.1063/1.4919062] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate atom-diatom reactive collisions, as a preliminary step,in order to assess the possibility of forming Rb(2) molecules in their lowest triplet electronic state by cold collisions of rubidium atoms on the surface of helium nanodroplets [corrected]. A simple model related to the well-known Rosen treatment of linear triatomic molecules [N. Rosen, J. Chem. Phys. 1, 319 (1933)] in relative coordinates is used, allowing to estimate reactive probabilities for different values of the total angular momentum. The best available full dimensional potential energy surface [Guillon et al., J. Chem. Phys. 136, 174307 (2012)] is employed through the calculations. Noticeable values of the probabilities in the ultracold regime, which numerically fulfill the Wigner threshold law, support the feasibility of the process. The rubidium dimer is mainly produced at high vibrational states, and the reactivity is more efficient for a bosonic helium partner than when the fermion species is considered.
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Affiliation(s)
| | | | - Rita Prosmiti
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, 28006 Madrid, Spain
| | | | - Pablo Villarreal
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, 28006 Madrid, Spain
| | - Julius Jellinek
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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16
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Pototschnig JV, Krois G, Lackner F, Ernst WE. Investigation of the RbCa molecule: Experiment and theory. JOURNAL OF MOLECULAR SPECTROSCOPY 2015; 310:126-134. [PMID: 25922550 PMCID: PMC4407902 DOI: 10.1016/j.jms.2015.01.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 01/12/2015] [Indexed: 06/04/2023]
Abstract
We present a thorough theoretical and experimental study of the electronic structure of RbCa. The mixed alkali-alkaline earth molecule RbCa was formed on superfluid helium nanodroplets. Excited states of the molecule in the range of 13 000-23 000 cm-1 were recorded by resonance enhanced multi-photon ionization time-of-flight spectroscopy. The experiment is accompanied by high level ab initio calculations of ground and excited state properties, utilizing a multireference configuration interaction method based on multiconfigurational self consistent field calculations. With this approach the potential energy curves and permanent electric dipole moments of 24 electronic states were calculated. In addition we computed the transition dipole moments for transitions from the ground into excited states. The combination of experiment and theory allowed the assignment of features in the recorded spectrum to the excited [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] states, where the experiment allowed to benchmark the calculation. This is the first experimental work giving insight into the previously unknown RbCa molecule, which offers great prospects in ultracold molecular physics due to its magnetic and electronic dipole moment in the [Formula: see text] ground state.
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17
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Krasnokutski SA, Huisken F. Resonant two-photon ionization spectroscopy of Al atoms and dimers solvated in helium nanodroplets. J Chem Phys 2015; 142:084311. [DOI: 10.1063/1.4908533] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Serge A. Krasnokutski
- Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena, Germany
| | - Friedrich Huisken
- Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena, Germany
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18
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Galinis G, Mendoza Luna LG, Watkins MJ, Ellis AM, Minns RS, Mladenović M, Lewerenz M, Chapman RT, Turcu ICE, Cacho C, Springate E, Kazak L, Göde S, Irsig R, Skruszewicz S, Tiggesbäumker J, Meiwes-Broer KH, Rouzée A, Underwood JG, Siano M, von Haeften K. Formation of coherent rotational wavepackets in small molecule-helium clusters using impulsive alignment. Faraday Discuss 2014; 171:195-218. [PMID: 25415646 DOI: 10.1039/c4fd00099d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We show that rotational line spectra of molecular clusters with near zero permanent dipole moments can be observed using impulsive alignment. Aligned rotational wavepackets were generated by non-resonant interaction with intense femtosecond laser pump pulses and then probed using Coulomb explosion by a second, time-delayed femtosecond laser pulse. By means of a Fourier transform a rich spectrum of rotational eigenstates was derived. For the smallest cluster, C(2)H(2)-He, we were able to establish essentially all rotational eigenstates up to the dissociation threshold on the basis of theoretical level predictions. The C(2)H(2)-He complex is found to exhibit distinct features of large amplitude motion and very early onset of free internal rotor energy level structure.
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Affiliation(s)
- Gediminas Galinis
- University of Leicester, Department of Physics & Astronomy, Leicester, LE1 7RH, UK.
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19
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Benedek G, Hizhnyakov V, Toennies JP. The Response of a 3He Fermi Liquid Droplet to Vibronic Excitation of an Embedded Glyoxal Molecule. J Phys Chem A 2014; 118:6574-83. [DOI: 10.1021/jp503184d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Giorgio Benedek
- Donostia
International Physics Center (DIPC), University of the Basque Country (EHU-UPV), Paseo de Lardizàbal 4, 20018 Donostia/San Sebastian, Spain
- Dipartimento
di Scienza dei Materiali, Università di Milano-Bicocca, Via
Cozzi 53, 20125 Milano, Italy
- Max-Planck Institut für Dynamik und Selbstorganisation, Am Fassberg 17, 37077 Göttingen, Germany
| | - Vladimir Hizhnyakov
- Institute
of Physics, University of Tartu, Riia tu. 142, 202400 Tartu, Estonia
| | - J. Peter Toennies
- Max-Planck Institut für Dynamik und Selbstorganisation, Am Fassberg 17, 37077 Göttingen, Germany
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20
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21
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Hernando A, Beswick JA, Halberstadt N. Communication: Angular momentum alignment and fluorescence polarization of alkali atoms photodetached from helium nanodroplets. J Chem Phys 2013; 139:221102. [DOI: 10.1063/1.4843235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Pentlehner D, Slenczka A. Electronic spectroscopy of 9,10-dichloroanthracene inside helium droplets. J Chem Phys 2013; 138:024313. [PMID: 23320689 DOI: 10.1063/1.4773894] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The spectroscopy of molecules doped into superfluid helium droplets provides information on both, the dopant molecule and the helium environment. Electronic spectra of 9,10-dichloroanthracene in helium droplets are presented and compared with corresponding gas phase spectra to unravel the influence of the helium environment. The combined investigation of fluorescence excitation and dispersed emission provides information on dynamic processes in addition to energetic conditions. For vibronic states, the helium induced decay channels dominate over all intramolecular channels that contribute to the gas phase behavior. In addition to the triplet splitting caused by the Cl isotopes, a fine structure resolved for all transitions in the fluorescence excitation spectrum was found, which is the signature of microsolvation of this compound in helium droplets. This fine structure is identified as a single pure molecular transition accompanied by a sharply structured phonon wing. The corresponding fine structure measured for bare anthracene shows remarkable differences.
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Affiliation(s)
- D Pentlehner
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany
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23
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Giese C, Mullins T, Grüner B, Weidemüller M, Stienkemeier F, Mudrich M. Formation and relaxation of RbHe exciplexes on He nanodroplets studied by femtosecond pump and picosecond probe spectroscopy. J Chem Phys 2012; 137:244307. [PMID: 23277936 DOI: 10.1063/1.4772749] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- C Giese
- Physikalisches Institut, Universität Freiburg, 79104 Freiburg, Germany
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24
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Benedek G, Hizhnyakov V. Fermi sea excitations in the optical spectrum of a doped 3He droplet. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.07.065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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25
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Hizhnyakov V. Zero-phonon lines of systems with different dimensions and unconventional vibronic interactions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:104011. [PMID: 22353367 DOI: 10.1088/0953-8984/24/10/104011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The standard theory of the optical spectra of impurity centres in solids predicts the Lorentzian shape of the zero-phonon lines to have temperature-dependent position and width. However, in recent years different systems, including ones of reduced dimension, have been found, in which remarkable deviations from the standard laws have been observed. Generalizations of the theory to these systems are presented. Among other things, the quantum liquid 3He doped by optical centres is considered.
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Affiliation(s)
- V Hizhnyakov
- Institute of Physics, University of Tartu, Tartu, Estonia.
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26
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López-Durán D, Rodríguez-Cantano R, González-Lezana T, Delgado-Barrio G, Villarreal P, Yurtsever E, Gianturco FA. Weakly bound finite systems: (⁴He)N-Rb₂(³Σu), clustering structures from a quantum Monte Carlo approach. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:104014. [PMID: 22353432 DOI: 10.1088/0953-8984/24/10/104014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report here ((4)He)(N)-Rb(2)((3)Σ(u)) complexes, 2 ≤ N ≤ 20, analysed through a quantum diffusion Monte Carlo stochastic approach. The calculations show that the spin stretched dimer molecule is bound outside the pure He sub-complex, due to the stronger He-He potential as compared with the He-Rb(2) interaction, while the rare gas atom moiety presents, in turn, a shell-like structure with ten He adatoms completing the first shell. Our results agree with previous findings on this and similarly weakly interacting systems.
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Affiliation(s)
- D López-Durán
- Instituto de Física Fundamental, CSIC, Serrano 123, 28006 Madrid, Spain
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27
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Fechner L, Grüner B, Sieg A, Callegari C, Ancilotto F, Stienkemeier F, Mudrich M. Photoionization and imaging spectroscopy of rubidium atoms attached to helium nanodroplets. Phys Chem Chem Phys 2012; 14:3843-51. [PMID: 22327348 DOI: 10.1039/c2cp22749e] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- L Fechner
- Physikalisches Institut, Universität Freiburg, Freiburg, Germany
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28
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Filsinger F, Ahn DS, Meijer G, von Helden G. Photoexcitation of mass/charge selected hemin+, caught in helium nanodroplets. Phys Chem Chem Phys 2012; 14:13370-7. [DOI: 10.1039/c2cp42071f] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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29
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Loginov E, Callegari C, Ancilotto F, Drabbels M. Spectroscopy on Rydberg States of Sodium Atoms on the Surface of Helium Nanodroplets. J Phys Chem A 2011; 115:6779-88. [PMID: 21446657 DOI: 10.1021/jp111146n] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Evgeniy Loginov
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédéral de Lausanne (EPFL),CH-1015 Lausanne, Switzerland
| | - Carlo Callegari
- Institute of Experimental Physics, TU Graz, Petersgasse 16, A-8010 Graz, Austria
| | - Francesco Ancilotto
- Dipartimento di Fisica, “G. Galilei”, Universita' di Padova, via Marzolo 8, I-35131 Padova, Italy and CNR-IOM-Democritos, I-34014 Trieste, Italy
| | - Marcel Drabbels
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédéral de Lausanne (EPFL),CH-1015 Lausanne, Switzerland
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30
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Grüner B, Schlesinger M, Heister P, Strunz WT, Stienkemeier F, Mudrich M. Vibrational relaxation and dephasing of Rb2 attached to helium nanodroplets. Phys Chem Chem Phys 2011; 13:6816-26. [PMID: 21394372 DOI: 10.1039/c0cp02355h] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The vibrational wave-packet dynamics of diatomic rubidium molecules (Rb(2)) in triplet states formed on the surface of superfluid helium nanodroplets is investigated both experimentally and theoretically. Detailed comparison of experimental femtosecond pump-probe spectra with dissipative quantum dynamics simulations reveals that vibrational relaxation is the main source of dephasing. The rate constant for vibrational relaxation in the first excited triplet state 1(3)Σ(g)+ is found to be constant γ ≈ 0.5 ns(-1) for the lowest vibrational levels v ≲ 15 and to increase sharply when exciting to higher energies.
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Affiliation(s)
- B Grüner
- Physikalisches Institut, Universität Freiburg, 79104 Freiburg, Germany
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31
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Forysinski PW, Zielke P, Luckhaus D, Corbett J, Signorell R. Photoionization of small sodium-doped acetic acid clusters. J Chem Phys 2011; 134:094314. [DOI: 10.1063/1.3559464] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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32
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Schöbel H, Bartl P, Leidlmair C, Daxner M, Zöttl S, Denifl S, Märk TD, Scheier P, Spångberg D, Mauracher A, Bohme DK. Sequential penning ionization: harvesting energy with ions. PHYSICAL REVIEW LETTERS 2010; 105:243402. [PMID: 21231525 DOI: 10.1103/physrevlett.105.243402] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Indexed: 05/30/2023]
Abstract
We report the observation of the ejection of electrons caused by collisions of excited atoms with ions, rather than neutrals, leading to the production of doubly charged ions. Doping superfluid He droplets with methyl iodide and exposing them to electrons enhances the formation of doubly charged iodine atoms at the threshold for the production of two metastable He atoms. These observations point toward a novel ionization process where doubly charged ions are produced by sequential Penning ionization. In some cases, depending on the neutral target, the process also leads to a subsequent Coulomb explosion of the dopant.
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Affiliation(s)
- Harald Schöbel
- Institute for Ion Physics and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria
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33
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Dissipative vibrational wave packet dynamics of alkali dimers attached to helium nanodroplets. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.03.060] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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34
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Kornilov O, Wang CC, Bünermann O, Healy AT, Leonard M, Peng C, Leone SR, Neumark DM, Gessner O. Ultrafast Dynamics in Helium Nanodroplets Probed by Femtosecond Time-Resolved EUV Photoelectron Imaging. J Phys Chem A 2009; 114:1437-45. [DOI: 10.1021/jp907312t] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Oleg Kornilov
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Chia C. Wang
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Oliver Bünermann
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Andrew T. Healy
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Mathew Leonard
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Chunte Peng
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Stephen R. Leone
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Daniel M. Neumark
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Oliver Gessner
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
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35
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Koch M, Lanzersdorfer J, Callegari C, Muenter JS, Ernst WE. Molecular Beam Magnetic Resonance in Doped Helium Nanodroplets. A Setup for Optically Detected ESR/NMR in the Presence of Unresolved Zeeman Splittings. J Phys Chem A 2009; 113:13347-56. [PMID: 19921944 DOI: 10.1021/jp9041827] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Markus Koch
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria/EU, and Department of Chemistry, University of Rochester, Rochester, New York 14627-0216
| | - Johannes Lanzersdorfer
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria/EU, and Department of Chemistry, University of Rochester, Rochester, New York 14627-0216
| | - Carlo Callegari
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria/EU, and Department of Chemistry, University of Rochester, Rochester, New York 14627-0216
| | - John S. Muenter
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria/EU, and Department of Chemistry, University of Rochester, Rochester, New York 14627-0216
| | - Wolfgang E. Ernst
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria/EU, and Department of Chemistry, University of Rochester, Rochester, New York 14627-0216
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36
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Bovino S, Coccia E, Bodo E, Lopez-Durán D, Gianturco FA. Spin-driven structural effects in alkali doped (4)He clusters from quantum calculations. J Chem Phys 2009; 130:224903. [PMID: 19530785 DOI: 10.1063/1.3147466] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this paper, we carry out variational Monte Carlo and diffusion Monte Carlo (DMC) calculations for Li(2)((1)Sigma(g) (+))((4)He)(N) and Li(2)((3)Sigma(u) (+))((4)He)(N) with N up to 30 and discuss in detail the results of our computations. After a comparison between our DMC energies with the "exact" discrete variable representation values for the species with one (4)He, in order to test the quality of our computations at 0 K, we analyze the structural features of the whole range of doped clusters. We find that both species reside on the droplet surface, but that their orientation is spin driven, i.e., the singlet molecule is perpendicular and the triplet one is parallel to the droplet's surface. We have also computed quantum vibrational relaxation rates for both dimers in collision with a single (4)He and we find them to differ by orders of magnitude at the estimated surface temperature. Our results therefore confirm the findings from a great number of experimental data present in the current literature and provide one of the first attempts at giving an accurate, fully quantum picture for the nanoscopic properties of alkali dimers in (4)He clusters.
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Affiliation(s)
- S Bovino
- Department of Chemistry and CNISM, The University of Rome Sapienza, P.le A. Moro 5, 00185 Rome, Italy
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37
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Snyder DN, Szczęśniak MM, Chałasiński G. The nature of interactions between clusters of Mg and Zn with HCN from symmetry-adapted perturbation theory based of DFT. J Chem Phys 2009; 130:224704. [DOI: 10.1063/1.3152122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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38
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Szalewicz K. Interplay between theory and experiment in investigations of molecules embedded in superfluid helium nanodroplets†. INT REV PHYS CHEM 2008. [DOI: 10.1080/01442350801933485] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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39
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Pacheco AB, Thorndyke B, Reyes A, Micha DA. Quantum dynamics of an excited alkali atom in a noble gas cluster: Lithium attached to a helium cluster. J Chem Phys 2007; 127:244504. [DOI: 10.1063/1.2813889] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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40
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Patkowski K, Podeszwa R, Szalewicz K. Interactions in Diatomic Dimers Involving Closed-Shell Metals. J Phys Chem A 2007; 111:12822-38. [DOI: 10.1021/jp076412c] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Konrad Patkowski
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716
| | - Rafał Podeszwa
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716
| | - Krzysztof Szalewicz
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716
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41
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Douberly GE, Miller RE. Rotational Dynamics of HCN−M (M = Na, K, Rb, Cs) van der Waals Complexes Formed on the Surface of Helium Nanodroplets. J Phys Chem A 2007; 111:7292-302. [PMID: 17602450 DOI: 10.1021/jp070042a] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Infrared laser spectroscopy was used to probe the unique rotational dynamics of the HCN-M (M = Na, K, Rb, Cs) complexes formed on the surface of helium droplets. The nu1 CH stretch ro-vibrational spectra were measured revealing what appears to be the P and R contours of a nearly rigid linear rotor. To simulate the linear molecule spectra, given a rotational temperature of 0.37 K, effective moments of inertia, IB, were required to be 10(4)-10(5) amu.A2 larger than the ab initio predicted values. The large moments of inertia were found to be strongly dependent on both the mass of the complex and the size of the helium droplet, consistent with a model where the dopant is located in a dimple site on the surface of the droplet. In this model, the moment of inertia is representative of the rotational motion of the dopant on the surface about an inertial axis through the center of the droplet.
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Affiliation(s)
- Gary E Douberly
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
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42
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Loginov E, Drabbels M. Excited State Dynamics of Ag Atoms in Helium Nanodroplets. J Phys Chem A 2007; 111:7504-15. [PMID: 17569515 DOI: 10.1021/jp0716278] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The excited state dynamics of silver atoms embedded in helium nanodroplets have been investigated by a variety of spectroscopic techniques. The experiments reveal that 5p 2P1/2 <-- 5s 2S1/2 excitation of embedded silver atoms results almost exclusively in the ejection of silver atoms populating the 2P1/2 state. In contrast, excitation to the 5p 2P3/2 state leads to the ejection of not only silver atoms in the 2P1/2, 2P3/2, and 2D5/2 excited states but also of AgHe and AgHe2. These AgHe exciplexes are mainly formed in the A2Pi1/2 electronic state. In addition, it is found that a considerable fraction of the 2P3/2 excited silver atoms become solvated within the helium droplets, most probably as AgHe2. The observations can be accounted for by a model in which the metastable 2D5/2 state of silver acts as a doorway state in the relaxation of 2P3/2 excited silver atoms.
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Affiliation(s)
- Evgeniy Loginov
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédéral de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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Claas P, Droppelmann G, Schulz CP, Mudrich M, Stienkemeier F. Wave Packet Dynamics in Triplet States of Na2 Attached to Helium Nanodroplets. J Phys Chem A 2007; 111:7537-41. [PMID: 17461563 DOI: 10.1021/jp070893i] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dynamics of vibrational wave packets excited in Na2 dimers in the triplet ground and excited states is investigated by means of helium nanodroplet isolation (HENDI) combined with femtosecond pump-probe spectroscopy. Different pathways in the employed resonant multiphoton ionization scheme are identified. Within the precision of the method, the wave packet dynamics appears to be unperturbed by the helium droplet environment.
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Affiliation(s)
- Patrick Claas
- Fakultät für Physik, Universität Bielefeld, 33615 Bielefeld, Germany
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Fárník M, Toennies JP. Ion-molecule reactions in 4He droplets: flying nano-cryo-reactors. J Chem Phys 2007; 122:14307. [PMID: 15638659 DOI: 10.1063/1.1815272] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ion-molecule reactions are studied inside large (approximately equal to 10(4) atoms) very cold (0.37 K) superfluid (4)He droplets by mass spectrometric detection of the product ions. He+ ions initially formed inside the droplets by electron impact ionization undergo charge transfer with either embedded D(2), N(2), or CH(4). For D(2) this charge transfer process was studied in detail by varying the pickup pressure. For either N(2) or CH(4) the reagent ions were formed by this charge transfer and the reaction pathways of the secondary reactions N(2) (+)+D(2), CH(4) (+)+D(2), and CH(3) (+)+D(2) each with an additionally embedded D(2) molecule were also determined from the pickup pressure dependencies. In several cases, notably He.N(2) (+) and CH(3)D(2) (+) reaction intermediates are observed. The analysis is facilitated by the tendency for molecular ion products to appear without (or with only very few) attached He atoms whereas the atomic ion products usually appear in the mass spectra with several attached He atoms, e.g., He(m).D+ ions with up to m=19.
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Affiliation(s)
- Michal Fárník
- Max-Planck Institut für Strömungsforschung, Bunsenstrasse 10, D-37073 Göttingen, Germany.
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Tiggesbäumker J, Stienkemeier F. Formation and properties of metal clusters isolated in helium droplets. Phys Chem Chem Phys 2007; 9:4748-70. [PMID: 17712454 DOI: 10.1039/b703575f] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The unique conditions forming atomic and molecular complexes and clusters using superfluid helium nanodroplets have opened up an innovative route for studying the physical and chemical properties of matter on the nanoscale. This review summarizes the specific characteristics of the formation of atomic clusters partly generated far from equilibrium in the helium environment. Special emphasis is on the optical response, electronic properties as well as dynamical processes which are mostly affected by the surrounding quantum matrix. Experiments include the optical induced response of isolated cluster systems in helium under quite different excitation conditions ranging from the linear regime up to the violent interaction with a strong laser field leading to Coulomb explosion and the generation of highly charged atomic fragments. The variety of results on the outstanding properties in the quantum size regime highlights the peculiar capabilities of helium nanodroplet isolation spectroscopy.
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Ernst WE, Huber R, Jiang S, Beuc R, Movre M, Pichler G. Cesium dimer spectroscopy on helium droplets. J Chem Phys 2006; 124:024313. [PMID: 16422589 DOI: 10.1063/1.2155431] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Visible absorption spectra of cesium-doped helium nanodroplets between 14,500 and 17,600 cm(-1) were probed by laser-induced fluorescence. A strong absorption band peaking around 16,700 cm(-1) is identified as Cs2 1(a) 3Sigmau+-3 3Sigmag+ transition. A broad unstructured band near 17,520 cm(-1) is assigned as the Cs2 1(X) 1Sigmag+-2 1Sigmau+ transition. Explanations of the observations are discussed on the basis of ab initio potential curves calculated by Spies and Meyer [(unpublished)]. All spectra have been modeled using narrow Frank-Condon windows around the equilibrium internuclear distance of the lowest singlet and triplet states. Many observed absorption peaks of smaller intensities could be identified, some of which may be due to transitions of cesium trimers formed on the droplets.
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Affiliation(s)
- W E Ernst
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
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Choi MY, Douberly GE, Falconer TM, Lewis WK, Lindsay CM, Merritt JM, Stiles PL, Miller RE. Infrared spectroscopy of helium nanodroplets: novel methods for physics and chemistry. INT REV PHYS CHEM 2006. [DOI: 10.1080/01442350600625092] [Citation(s) in RCA: 327] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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48
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Bünermann O, Mudrich M, Weidemüller M, Stienkemeier F. Spectroscopy of Cs attached to helium nanodroplets. J Chem Phys 2004; 121:8880-6. [PMID: 15527352 DOI: 10.1063/1.1805508] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cesium oligomers are formed on helium nanodroplets which are doped with one or a few Cs atoms. The monomer absorption of the first electronic p<--s transition upon laser excitation is probed. Spectra employing laser-induced fluorescence, beam depletion, and resonant photoionization are compared. In particular, mass-resolved photoionization allows us to specifically probe excitation induced processes such as, e.g., the formation of cesium-helium exciplexes. Absorption spectra of Cs dimers and trimers are recorded in the spectral region accessible by a Ti:sapphire laser. Assignment of dimer spectra is achieved by comparison with model calculations based on ab initio potentials. Electronic absorption lines of Cs trimers are attributed to transitions in the quartet manifold.
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Affiliation(s)
- O Bünermann
- Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
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49
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Droppelmann G, Bünermann O, Schulz CP, Stienkemeier F. Formation times of RbHe exciplexes on the surface of superfluid versus normal fluid helium nanodroplets. PHYSICAL REVIEW LETTERS 2004; 93:023402. [PMID: 15323914 DOI: 10.1103/physrevlett.93.023402] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Indexed: 05/24/2023]
Abstract
Nanodroplets of either superfluid 4He or normal fluid 3He are doped with Rb atoms that are bound to the surface of the droplets. The formation of RbHe exciplexes upon 5P(3/2) excitation is monitored in real time by femtosecond pump-probe techniques. We find formation times of 8.5 and 11.6 ps for Rb 4He and Rb 3He, respectively. A comparison to calculations based on a tunneling model introduced for these systems by Reho et al. [J. Chem. Phys. 113, 9694 (2000)]] shows that the proposed mechanism cannot account for our findings. Apparently, a different relaxation dynamics of the superfluid opposed to the normal fluid surface is responsible for the observed formation times.
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Affiliation(s)
- G Droppelmann
- Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
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50
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Bodo E, Sebastianelli F, Gianturco FA, Yurtsever E, Yurtsever M. Ab initio quantum dynamics with very weak van der Waals interactions: Structure and stability of small Li2(1Sigmag+)-(He)n clusters. J Chem Phys 2004; 120:9160-6. [PMID: 15267852 DOI: 10.1063/1.1701834] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The potential energy surface (PES) for the interaction between Li2(1Sigmag+) and 4He has been computed using an accurate, post-Hartree-Fock quantum calculation for its ground electronic state. The orientational anisotropy of the forces and the interplay between repulsive and attractive effects within the PES are analyzed to extract information on the possible existence of bound states in the triatomic system. The structures of a few of the Li2(He)n small clusters are examined by comparing a classical approach with a full quantum one to generate bound configurations and to extract information on the possible spatial arrangements of the smaller clusters via à vis the location of the Li2 dopant. Some significant consequences on the Li2 behavior in larger clusters and droplets are drawn from the above findings.
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Affiliation(s)
- E Bodo
- Department of Chemistry and INFM, University of Rome La Sapienza, Italy
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