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Schlaghaufer F, Slenczka A. Electronic spectroscopy of phthalocyanine in a supersonic jet revisited. Phys Chem Chem Phys 2022; 24:20921-20931. [PMID: 36018327 DOI: 10.1039/d2cp02256g] [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
Spectroscopic investigation of phthalocyanine in the gas phase has tremendously profited from molecular beam spectroscopy. Isentropic expansion succeeds in reducing the population of rovibrational states to the vibrational ground state so that only low energy rotational states remain populated. However, with respect to UV-vis spectroscopy the pioneers of molecular beam spectroscopy came to the discouraging conclusion that the information contained in the rotational structure of a large molecule is minimal, and even if the rotational structure could be resolved with great effort, the results are unlikely to be worth the difficulty [Levy, Annu. Rev. Phys. Chem., 1980, 31 197-225]. Just over 4 decades later we would like to announce that the result is worth the effort, indeed. Even without full line resolution, the rotational structure at the electronic band origin of phthalocyanine provides deep insight into configurational details of phthalocyanine for both electronic states. These details serve as gas phase compliment to the investigation of microsolvation in superfluid helium droplets. To the best of our knowledge this is the largest molecule ever analyzed by means of its rotational degrees of freedom.
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Affiliation(s)
- Florian Schlaghaufer
- Institute for Physical and Theoretical Chemistry, University of Regensburg, Regensburg, Germany.
| | - Alkwin Slenczka
- Institute for Physical and Theoretical Chemistry, University of Regensburg, Regensburg, Germany.
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2
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Bergmeister S, Kollotzek S, Calvo F, Gruber E, Zappa F, Scheier P, Echt O. Adsorption of Helium and Hydrogen on Triphenylene and 1,3,5-Triphenylbenzene. Molecules 2022; 27:molecules27154937. [PMID: 35956887 PMCID: PMC9370105 DOI: 10.3390/molecules27154937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 11/16/2022] Open
Abstract
The adsorption of helium or hydrogen on cationic triphenylene (TPL, C18H12), a planar polycyclic aromatic hydrocarbon (PAH) molecule, and of helium on cationic 1,3,5-triphenylbenzene (TPB, C24H18), a propeller-shaped PAH, is studied by a combination of high-resolution mass spectrometry and classical and quantum computational methods. Mass spectra indicate that HenTPL+ complexes are particularly stable if n = 2 or 6, in good agreement with the quantum calculations that show that for these sizes, the helium atoms are strongly localized on either side of the central carbon ring for n = 2 and on either side of the three outer rings for n = 6. Theory suggests that He14TPL+ is also particularly stable, with the helium atoms strongly localized on either side of the central and outer rings plus the vacancies between the outer rings. For HenTPB+, the mass spectra hint at enhanced stability for n = 2, 4 and, possibly, 11. Here, the agreement with theory is less satisfactory, probably because TPB+ is a highly fluxional molecule. In the global energy minimum, the phenyl groups are rotated in the same direction, but when the zero-point harmonic correction is included, a structure with one phenyl group being rotated opposite to the other two becomes lower in energy. The energy barrier between the two isomers is very small, and TPB+ could be in a mixture of symmetric and antisymmetric states, or possibly even vibrationally delocalized.
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Affiliation(s)
- Stefan Bergmeister
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria; (S.B.); (S.K.); (E.G.); (F.Z.); (P.S.)
| | - Siegfried Kollotzek
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria; (S.B.); (S.K.); (E.G.); (F.Z.); (P.S.)
| | - Florent Calvo
- Laboratoire Interdisciplinaire de Physique, CNRS, Université Grenoble Alpes, F-38000 Grenoble, France
- Correspondence: (F.C.); (O.E.)
| | - Elisabeth Gruber
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria; (S.B.); (S.K.); (E.G.); (F.Z.); (P.S.)
| | - Fabio Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria; (S.B.); (S.K.); (E.G.); (F.Z.); (P.S.)
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria; (S.B.); (S.K.); (E.G.); (F.Z.); (P.S.)
| | - Olof Echt
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria; (S.B.); (S.K.); (E.G.); (F.Z.); (P.S.)
- Department of Physics, University of New Hampshire, Durham, NH 03824, USA
- Correspondence: (F.C.); (O.E.)
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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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High-resolution two-dimensional electronic spectroscopy reveals the homogeneous line profile of chromophores solvated in nanoclusters. Nat Commun 2022; 13:3350. [PMID: 35688839 PMCID: PMC9187667 DOI: 10.1038/s41467-022-31021-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 05/24/2022] [Indexed: 11/16/2022] Open
Abstract
Doped clusters in the gas phase provide nanoconfined model systems for the study of system-bath interactions. To gain insight into interaction mechanisms between chromophores and their environment, the ensemble inhomogeneity has to be lifted and the homogeneous line profile must be accessed. However, such measurements are very challenging at the low particle densities and low signal levels in cluster beam experiments. Here, we dope cryogenic rare-gas clusters with phthalocyanine molecules and apply action-detected two-dimensional electronic spectroscopy to gain insight into the local molecule-cluster environment for solid and superfluid cluster species. The high-resolution homogeneous linewidth analysis provides a benchmark for the theoretical modelling of binding configurations and shows a promising route for high-resolution molecular two-dimensional spectroscopy. Understanding the interaction of single chromophores with nanoparticles remains a challenging task in nanoscience. Here the authors provide insight into the interaction between isolated base-free phthalocyanine molecules and He and Ne nanoclusters in the gas phase using high-resolution two-dimensional spectroscopy.
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Bohlen M, Michiels R, Michelbach M, Ferchane S, Walter M, Eisfeld A, Stienkemeier F. Excitation dynamics in polyacene molecules on rare-gas clusters. J Chem Phys 2022; 156:034305. [DOI: 10.1063/5.0073503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Matthias Bohlen
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Rupert Michiels
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Moritz Michelbach
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Selmane Ferchane
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Michael Walter
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
- FIT Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
- Fraunhofer IWM, MikroTribologie Centrum μTC, Wöhlerstr. 11, 79108 Freiburg, Germany
| | - Alexander Eisfeld
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, 01187 Dresden, Germany
| | - Frank Stienkemeier
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
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6
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Bogomolov AS, Rogoveshko VM, Baklanov AV. The first shell structure of He environment in tetracene-(He)N clusters manifested in REMPI spectra. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2021.139286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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8
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Lottner EM, Slenczka A. Anthracene-Argon Clusters Generated in Superfluid Helium Nanodroplets: New Aspects on Cluster Formation and Microsolvation. J Phys Chem A 2020; 124:311-321. [PMID: 31257886 DOI: 10.1021/acs.jpca.9b04138] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
About two decades after extensive studies on anthracene-Arn clusters in the gas phase, we report corresponding studies in superfluid helium droplets. With AN as a small fluorophore and spectroscopic data from the gas phase and helium droplets, both the formation of clusters and the microsolvation in superfluid helium droplets can be studied. As expected for helium droplets, a significantly higher number of isomeric variants of the respective cluster sizes are obtained, because metastable variants are stabilized by the low temperature and the surrounding helium. Moreover, spectroscopic data recorded in helium droplets reveal cluster configurations with Ar atoms shielded by a helium solvation layer. Surprisingly, AN-Arn clusters with more than four Ar atoms do not appear to form rigid configurations. The helium droplet data in combination with the gas phase spectra may serve as a suitable reference for further theoretical investigations on solvation and cluster formation in superfluid helium droplets.
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Affiliation(s)
- E-M Lottner
- Institut für Physikalische und Theoretische Chemie , Universität Regensburg , 93053 Regensburg , Germany
| | - A Slenczka
- Institut für Physikalische und Theoretische Chemie , Universität Regensburg , 93053 Regensburg , Germany
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Electronic Spectroscopy of Phthalocyanine and Porphyrin Derivatives in Superfluid Helium Nanodroplets. Molecules 2017; 22:molecules22081244. [PMID: 28757568 PMCID: PMC6152379 DOI: 10.3390/molecules22081244] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 07/19/2017] [Indexed: 11/25/2022] Open
Abstract
Phthalocyanine and porphyrin were among the first organic compounds investigated by means of electronic spectroscopy in superfluid helium nanodroplets. Superfluid helium nanodroplets serve as a very gentle host system for preparing cold and isolated molecules. The uniqueness of helium nanodroplets is with respect to the superfluid phase which warrants the vanishing viscosity and, thus, minimal perturbation of the dopant species at a temperature as low as 0.37 K. These are ideal conditions for the study of molecular spectra in order to analyze structures as well as dynamic processes. Besides the investigation of the dopant species itself, molecular spectroscopy in helium droplets provides information on the helium droplet and in particular on microsolvation. This article, as part of a special issue on phthalocyanines and porphyrins, reviews electronic spectroscopy of phthalocyanine and porphyrin compounds in superfluid helium nanodroplets. In addition to the wide variety of medical as well as technical and synthetical aspects, this article discusses electronic spectroscopy of phthalocyanines and porphyrins in helium droplets in order to learn about both the dopant and the helium environment.
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Rodríguez-Cantano R, Bartolomei M, Hernández MI, Campos-Martínez J, González-Lezana T, Villarreal P, Pérez de Tudela R, Pirani F, Hernández-Rojas J, Bretón J. Comparative investigation of pure and mixed rare gas atoms on coronene molecules. J Chem Phys 2017; 146:034302. [DOI: 10.1063/1.4973890] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
| | | | - 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
| | | | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Universitá di Perugia, 06123 Perugia, Italy
| | | | - José Bretón
- Departamento de Física and IUdEA, Universidad de La Laguna, 38205 Tenerife, Spain
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11
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Calvo F, Yurtsever E. Solvation of carbonaceous molecules by para-H2 and ortho-D2 clusters. I. Polycyclic aromatic hydrocarbons. J Chem Phys 2016; 144:224302. [DOI: 10.1063/1.4952957] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- F. Calvo
- Univ. Grenoble Alpes, LIPHY, F-38000 Grenoble, France and CNRS, LIPHY, F-38000 Grenoble, France
| | - E. Yurtsever
- Koç University, Rumelifeneriyolu, Sariyer, Istanbul 34450, Turkey
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Calvo F, Yurtsever E, Birer Ö. Possible Formation of Metastable PAH Dimers upon Pickup by Helium Droplets. J Phys Chem A 2016; 120:1727-36. [DOI: 10.1021/acs.jpca.5b12394] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- F. Calvo
- Univ. Grenoble Alpes, LIPHY, F-38000 Grenoble, France
- CNRS, LIPHY, F-38000 Grenoble, France
| | - E. Yurtsever
- Koç University, Chemistry Department, Rumeli
Feneri Yolu, Sariyer 34450, Istanbul, Turkey
| | - Ö. Birer
- Koç University, Chemistry Department, Rumeli
Feneri Yolu, Sariyer 34450, Istanbul, Turkey
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13
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Rodríguez-Cantano R, Pérez de Tudela R, Bartolomei M, Hernández MI, Campos-Martínez J, González-Lezana T, Villarreal P, Hernández-Rojas J, Bretón J. Coronene molecules in helium clusters: Quantum and classical studies of energies and configurations. J Chem Phys 2015; 143:224306. [DOI: 10.1063/1.4936414] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | | | | | - 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
| | | | - José Bretón
- Departamento de Física and IUdEA, Universidad de La Laguna, 38205 Tenerife, Spain
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14
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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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15
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Pentlehner D, Slenczka A. Helium induced fine structure in the electronic spectra of anthracene derivatives doped into superfluid helium nanodroplets. J Chem Phys 2015; 142:014311. [PMID: 25573565 DOI: 10.1063/1.4904899] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Electronic spectra of organic molecules doped into superfluid helium nanodroplets show characteristic features induced by the helium environment. Besides a solvent induced shift of the electronic transition frequency, in many cases, a spectral fine structure can be resolved for electronic and vibronic transitions which goes beyond the expected feature of a zero phonon line accompanied by a phonon wing as known from matrix isolation spectroscopy. The spectral shape of the zero phonon line and the helium induced phonon wing depends strongly on the dopant species. Phonon wings, for example, are reported ranging from single or multiple sharp transitions to broad (Δν > 100 cm(-1)) diffuse signals. Despite the large number of example spectra in the literature, a quantitative understanding of the helium induced fine structure of the zero phonon line and the phonon wing is missing. Our approach is a systematic investigation of related molecular compounds, which may help to shed light on this key feature of microsolvation in superfluid helium droplets. This paper is part of a comparative study of the helium induced fine structure observed in electronic spectra of anthracene derivatives with particular emphasis on a spectrally sharp multiplet splitting at the electronic origin. In addition to previously discussed species, 9-cyanoanthracene and 9-chloroanthracene will be presented in this study for the first time.
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Affiliation(s)
- D Pentlehner
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany
| | - A Slenczka
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany
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16
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Zhang X, Drabbels M. Elementary Excitations of Superfluid Helium Droplets Probed by Ion Spectroscopy. J Phys Chem Lett 2014; 5:3100-3105. [PMID: 26276319 DOI: 10.1021/jz501530e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Electronic spectra of molecules in helium droplets reveal spectral features that are related to the elementary excitations of the superfluid helium environment. In order to determine to what extent the interaction strength of the molecule with the helium affects these excitations, the spectrum corresponding to the B̃(2)A″ ← X̃ (2)A″ transition of 2,5-difluorophenol cations in helium droplets has been recorded. The vibronic resonances reveal a sharp zero-phonon line whose width is largely determined by the rotational band contour, followed by a broad structureless phonon wing at higher frequencies. The splitting between the zero-phonon line and phonon wing is approximately half of that found for neutral 2,5-difluorophenol. This difference is attributed to the increased helium density around the ion due to its strong interaction with the helium.
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Affiliation(s)
- Xiaohang Zhang
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Marcel Drabbels
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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17
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Premke T, Wirths EM, Pentlehner D, Riechers R, Lehnig R, Vdovin A, Slenczka A. Microsolvation of molecules in superfluid helium nanodroplets revealed by means of electronic spectroscopy. Front Chem 2014; 2:51. [PMID: 25077143 PMCID: PMC4100322 DOI: 10.3389/fchem.2014.00051] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 06/25/2014] [Indexed: 11/13/2022] Open
Abstract
The empirical model explaining microsolvation of molecules in superfluid helium droplets proposes a non-superfluid helium solvation layer enclosing the dopant molecule. This model warrants an empirical explanation of any helium induced substructure resolved for electronic transitions of molecules in helium droplets. Despite a wealth of such experimental data, quantitative modeling of spectra is still in its infancy. The theoretical treatment of such many-particle systems dissolved into a quantum fluid is a challenge. Moreover, the success of theoretical activities relies also on the accuracy and self-critical communication of experimental data. This will be elucidated by a critical resume of our own experimental work done within the last ten years. We come to the conclusion that spectroscopic data and among others in particular the spectral resolution depend strongly on experimental conditions. Moreover, despite the fact that none of the helium induced fine structure speaks against the empirical model for solvation in helium droplets, in many cases an unequivocal assignment of the spectroscopic details is not possible. This ambiguity needs to be considered and a careful and critical communication of experimental results is essential in order to promote success in quantitatively understanding microsolvation in superfluid helium nanodroplets.
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Affiliation(s)
- Tobias Premke
- Faculty for Chemistry and Pharmacy, Institute for Physical and Theoretical Chemistry, University of Regensburg Regensburg, Germany
| | - Eva-Maria Wirths
- Faculty for Chemistry and Pharmacy, Institute for Physical and Theoretical Chemistry, University of Regensburg Regensburg, Germany
| | | | | | | | | | - Alkwin Slenczka
- Faculty for Chemistry and Pharmacy, Institute for Physical and Theoretical Chemistry, University of Regensburg Regensburg, Germany
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Riechers R, Pentlehner D, Slenczka A. Microsolvation in superfluid helium droplets studied by the electronic spectra of six porphyrin derivatives and one chlorine compound. J Chem Phys 2014; 138:244303. [PMID: 23822240 DOI: 10.1063/1.4811199] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
After almost two decades of high resolution molecular spectroscopy in superfluid helium droplets, the understanding of microsolvation is still the subject of intense experimental and theoretical research. According to the published spectroscopic work including microwave, infrared, and electronic spectroscopy, the latter appears to be particularly promising to study microsolvation because of the appearance of pure molecular transitions and spectrally separated phonon wings. Instead of studying the very details of the influence of the helium environment for one particular dopant molecule as previously done for phthalocyanine, the present study compares electronic spectra of a series of non-polar porphyrin derivatives when doped into helium droplets consisting of 10(4)-10(5) helium atoms. Thereby, we focus on the helium-induced fine structure, as revealed most clearly at the corresponding electronic origin. The interpretation and the assignment of particular features obtained in the fluorescence excitation spectra are based on additional investigations of dispersed emission spectra and of the saturation behavior. Besides many dopant-specific results, the experimental study provides strong evidence for a particular triple peak feature representing the characteristic signature of helium solvation for all seven related dopant species.
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Affiliation(s)
- R Riechers
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany
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Shepperson B, Tandy J, Boatwright A, Feng C, Spence D, Shirley A, Yang S, Ellis AM. Electronic Spectroscopy of Toluene in Helium Nanodroplets: Evidence for a Long-Lived Excited State. J Phys Chem A 2013; 117:13591-5. [DOI: 10.1021/jp407577m] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Benjamin Shepperson
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, U.K
| | - Jon Tandy
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, U.K
| | - Adrian Boatwright
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, U.K
| | - Cheng Feng
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, U.K
| | - Daniel Spence
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, U.K
| | - Andrew Shirley
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, U.K
| | - Shengfu Yang
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, U.K
| | - Andrew M. Ellis
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, U.K
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20
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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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22
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Pörtner N, Toennies JP, Vilesov AF, Stienkemeier F. Anomalous fine structures of the 000band of tetracene in large He droplets and their dependence on droplet size. Mol Phys 2012. [DOI: 10.1080/00268976.2012.679633] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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23
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Zhang X, Brauer NB, Berden G, Rijs AM, Drabbels M. Mid-infrared spectroscopy of molecular ions in helium nanodroplets. J Chem Phys 2012; 136:044305. [DOI: 10.1063/1.3678011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Whitley HD, DuBois JL, Whaley KB. Theoretical Analysis of the Anomalous Spectral Splitting of Tetracene in 4He Droplets. J Phys Chem A 2011; 115:7220-33. [DOI: 10.1021/jp2003003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Heather D. Whitley
- Department of Chemistry and Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley, California 94720, United States
- Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, United States
| | - Jonathan L. DuBois
- Department of Chemistry and Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley, California 94720, United States
- Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, United States
| | - K. Birgitta Whaley
- Department of Chemistry and Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley, California 94720, United States
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25
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Kuma S, Nakahara H, Tsubouchi M, Takahashi A, Mustafa M, Sim G, Momose T, Vilesov AF. Laser Induced Fluorescence Spectroscopy of Tetracene with Large Ar, Ne, and H2 Clusters in Superfluid He Nanodroplets. J Phys Chem A 2011; 115:7392-9. [DOI: 10.1021/jp203341r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Susumu Kuma
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Hiroko Nakahara
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Masaaki Tsubouchi
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Akira Takahashi
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Majd Mustafa
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Goeun Sim
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Takamasa Momose
- Department of Chemistry, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Andrey F. Vilesov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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26
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Pentlehner D, Riechers R, Vdovin A, Pötzl GM, Slenczka A. Electronic spectroscopy of molecules in superfluid helium nanodroplets: an excellent sensor for intramolecular charge redistribution. J Phys Chem A 2011; 115:7034-43. [PMID: 21615111 DOI: 10.1021/jp112351u] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electronic spectra of molecules doped into superfluid (4)He nanodroplets reveal important details of the microsolvation in superfluid helium. The vibrational fine structure in the electronic spectra of phthalocyanine derivatives and pyrromethene dye molecules doped into superfluid helium droplets have been investigated. Together with previous studies on anthracene derivatives [J. Chem. Phys.2010, 133, 114505] and 3-hydroxyflavone [J. Chem. Phys.2009, 131, 194307], the line shapes vary between two limiting cases, namely, sharp Lorentzians and nonresolved vibrational fine structure. All different spectral signatures are initiated by the same effect, namely, the change of the electron density distribution initiated by the electronic excitation. This change can be quantified by the difference of the electrostatic moments of the molecule in the electronic ground state and the corresponding Franck-Condon point in the excited state. According to the experimental data, electronic spectroscopy suffers from drastic line broadening when accompanied by significant changes of the charge distribution, in particular, changes of the dipole moment. Vice versa, the vibrational fine structure in electronic spectra of molecules doped into helium droplets is highly sensitive to changes of the electron density distribution.
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Affiliation(s)
- D Pentlehner
- Institut für Physikalische und Theoretische Chemie Universität Regensburg, 93040 Regensburg, Germany
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27
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Stromeck-Faderl A, Pentlehner D, Kensy U, Dick B. High-Resolution Electronic Spectroscopy of the BODIPY Chromophore in Supersonic Beam and Superfluid Helium Droplets. Chemphyschem 2011; 12:1969-80. [DOI: 10.1002/cphc.201001076] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2010] [Indexed: 11/12/2022]
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28
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Makarewicz J. Ab initio potential energy surface and intermolecular vibrations of the naphthalene-argon van der Waals complex. J Chem Phys 2011; 134:064322. [DOI: 10.1063/1.3555765] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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29
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Pentlehner D, Greil C, Dick B, Slenczka A. Line broadening in electronic spectra of anthracene derivatives inside superfluid helium nanodroplets. J Chem Phys 2010; 133:114505. [DOI: 10.1063/1.3479583] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- D Pentlehner
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany
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30
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Smolarek S, Rijs AM, Buma WJ, Drabbels M. Absorption spectroscopy of adenine, 9-methyladenine, and 2-aminopurine in helium nanodroplets. Phys Chem Chem Phys 2010; 12:15600-6. [DOI: 10.1039/c0cp00746c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Whitley HD, DuBois JL, Whaley KB. Spectral shifts and helium configurations in 4He(N)-tetracene clusters. J Chem Phys 2009; 131:124514. [PMID: 19791901 DOI: 10.1063/1.3236386] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Spectral shifts of electronic transitions of tetracene in helium droplets are investigated in a theoretical study of (4)He(N)-tetracene clusters with 1 < or = N < or = 150. Utilizing a pairwise interaction for the S(0) state of tetracene with helium that is extended by semiempirical terms to construct a potential for the S(1) state of tetracene with helium, the spectral shift is calculated from path integral Monte Carlo calculations of the helium equilibrium properties with tetracene in the S(0) and S(1) states at T = 0 and at T = 0.625 K. The calculated spectral shifts are in quantitative agreement with available experimental measurements for small values of N (< or = 8) at T approximately 0.4 K and show qualitative agreement for larger N (10-20). The extrapolated value of the spectral shift in large droplets (N approximately 10(4)) is approximately 90% of the experimentally measured value. We find no evidence of multiple configurations of helium for any cluster size for either the S(0) or S(1) state of tetracene. These results suggest that the observed spectral splitting of electronic transitions of tetracene in large helium droplets is not due to the coexistence of static metastable helium densities, unlike the situation previously analyzed for the phthalocyanine molecule.
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Affiliation(s)
- Heather D Whitley
- Department of Chemistry and Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley, California 94720, USA.
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32
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Gibbons BR, Xu M, Bačić Z. Quantum Dynamics of the Vibrations of Helium Bound to the Nanosurface of a Large Planar Organic Molecule: Phthalocyanine·He van der Waals Complex. J Phys Chem A 2009; 113:3789-98. [DOI: 10.1021/jp809410s] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | - Minzhong Xu
- Department of Chemistry, New York University, New York, New York 10003
| | - Zlatko Bačić
- Department of Chemistry, New York University, New York, New York 10003
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33
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Lehnig R, Pentlehner D, Vdovin A, Dick B, Slenczka A. Photochemistry of 3-hydroxyflavone inside superfluid helium nanodroplets. J Chem Phys 2009; 131:194307. [DOI: 10.1063/1.3262707] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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34
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Loginov E, Braun A, Drabbels M. A new sensitive detection scheme for helium nanodroplet isolation spectroscopy: application to benzene. Phys Chem Chem Phys 2008; 10:6107-14. [DOI: 10.1039/b808211a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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35
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Birer Ö, Moreschini P, Lehmann KK. Electronic spectroscopy of benzo[g,h,i]perylene and coronene inside helium nanodroplets. Phys Chem Chem Phys 2008; 10:1648-57. [DOI: 10.1039/b717307e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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Malloci G, Mulas G, Cappellini G, Joblin C. Time-dependent density functional study of the electronic spectra of oligoacenes in the charge states −1, 0, +1, and +2. Chem Phys 2007. [DOI: 10.1016/j.chemphys.2007.07.046] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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37
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Birer O, Moreschini P, Lehmann KK, Scoles G. Electronic Spectroscopy of Nonalternant Hydrocarbons Inside Helium Nanodroplets. J Phys Chem A 2007; 111:12200-9. [PMID: 17880187 DOI: 10.1021/jp071175z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have recorded the electronic spectra of three polycyclic aromatic hydrocarbons (acenaphtylene, fluoranthene, and benzo(k)fluoranthene) containing a five-member ring and their van der Waals complexes with argon and oxygen with a molecular beam superfluid helium nanodroplet spectrometer. Although the molecules, which differ by addition of one or two fused benzene rings to acenaphtylene, have the same point group symmetry, the spectral lineshapes show distinct differences in the number of zero phonon lines and shapes of the phonon wings. Whereas the smallest molecule (acenaphtylene) has the most complicated line shape, the largest molecule (benzo(k)fluoranthene) shows different lineshapes for different vibronic transitions. The van der Waals complexes of fluoranthene exhibit more peaks than the theoretically allowed number of isomeric complexes with argon/oxygen. The current models of molecular solvation in liquid helium do not adequately explain these discrepancies.
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Affiliation(s)
- Ozgür Birer
- Chemistry Department, Princeton University, Princeton, New Jersey 08544, USA
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38
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Xu M, Bacić Z. Wave function delocalization and large-amplitude vibrations of helium on corrugated aromatic microsurfaces: tetracene.He and pentacene.He van der Waals complexes. J Phys Chem A 2007; 111:7653-63. [PMID: 17530836 DOI: 10.1021/jp072218e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report accurate quantum three-dimensional calculations of highly excited intermolecular vibrational states of the van der Waals (vdW) complexes tetracene.He and pentacene.He in the S1 excited electronic state. The aromatic molecules were taken to be rigid and the intermolecular potential energy surfaces (IPESs) were modeled as a sum of atom-atom Lennard-Jones pair potentials. The IPESs are corrugated in the direction of the long (x) axis of the aromatic molecules, due to the presence of the symmetrically equivalent global double minimum for tetracene.He, and a triple minimum (central global minimum and two equivalent local minima) for pentacene.He, on each side of the aromatic plane. Both IPESs have two additional minor equivalent local minima further away from the center of the molecule. The vdW vibrational states analyzed in this work cover about 80% of the well depths of the IPESs. The mode coupling is generally weak for those states whose out-of-plane (z) mode is unexcited. However, the z-mode fundamental is strongly coupled to the short-axis (y) in-plane mode, so that the pure z-mode excitation could not be identified. The He atom exhibits large in-plane spatial delocalizaton already in the ground vdW vibrational state, which increases rapidly upon the excitation of the in-plane x and y modes, with little hindrance by the corrugation of the aromatic microsurfaces. For the vdW vibrational energies considered, the He atom spatial delocalization reaches Deltax and Deltay values of approximately 5 and 4 A, respectively, and is limited only by the finite size of the aromatic substrates. Side-crossing delocalization of the wave functions on both sides of the molecular plane is found at excitation energies >30 cm(-1), giving rise to the energy splittings of the pairs of states symmetric/antisymmetric with respect to the aromatic plane; the splittings show strong vdW vibrational mode specificity.
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Affiliation(s)
- Minzhong Xu
- Department of Chemistry, New York University, New York, New York 10003, USA
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39
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Birer O, Moreschini P, Lehmann KK, Scoles G. Electronic Spectroscopy of Biphenylene Inside Helium Nanodroplets. J Phys Chem A 2007; 111:7624-30. [PMID: 17580829 DOI: 10.1021/jp070741n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have recorded the S1 <-- S0 electronic spectra of Biphenylene and its Ar and O2 van der Waals complexes inside helium nanodroplets using beam depletion detection. In general, the spectrum is similar to the previously reported high-resolution REMPI spectrum. The zero phonon lines, however, are split similar to the previously reported tetracene case. The calculated potential energy surface predicts that helium atoms can simultaneously occupy all equivalent global minima positions. Therefore, it appears that the splitting cannot be explained either by different isomers or by tunneling. Furthermore, surprisingly the splitting is retained for the Ar van der Waals complexes (and possibly for the O2 complex as well). This case suggests that the current models of the origin of zero phonon line splitting and the helium solvation are incomplete.
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Affiliation(s)
- Ozgür Birer
- Chemistry Department, Princeton University, Princeton, New Jersey 08544, USA
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40
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Auböck G, Nagl J, Callegari C, Ernst WE. Triplet State Excitation of Alkali Molecules on Helium Droplets: Experiments and Theory. J Phys Chem A 2007; 111:7404-10. [PMID: 17552501 DOI: 10.1021/jp070891y] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper, we discuss the electronic structure of alkali dimer molecules in 3Pig states on the surface of a helium droplet. The perturbation due to the droplet will in general not satisfy rotational symmetry around the internuclear axis of the diatom and thus, in addition to a broadening and blue shift, will cause a splitting of electronic levels that are degenerate in the free molecules. We propose a model based on general symmetry arguments and on a small number of physically reasonable parameters. We demonstrate that such a model accounts for the essential features of laser-induced fluorescence (LIF) and magnetic circular dichroism (MCD) spectra of the (1)3Pig-a3Sigma+ transition of Rb2 and K2. Furthermore the MCD spectra, analyzed according to the approach of Langford and Williamson [J. Phys. Chem. A 1998, 102, 2415], allow a determination of the populations of Zeeman sublevels in the ground state and thus a measurement of the surface temperature of the droplet. The latter agrees with the accepted temperature, 0.37 K, measured in the interior of a droplet.
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Affiliation(s)
- Gerald Auböck
- Institute of Experimental Physics, TU Graz, Petersgasse 16, 8010 Graz, Austria, EU
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41
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Przystawik A, Radcliffe P, Diederich T, Döppner T, Tiggesbäumker J, Meiwes-Broer KH. Photoelectron studies of neutral Ag3 in helium droplets. J Chem Phys 2007; 126:184306. [PMID: 17508802 DOI: 10.1063/1.2723087] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Photoelectron spectra of neutral silver trimers, grown in ultracold helium nanodroplets, are recorded after ionization with laser pulses via a strong optical resonance of this species. Varying the photon energy reveals that direct vertical two-photon ionization is hindered by a rapid relaxation into the lower edge of a long-living excited state manifold. An analysis of the ionization threshold of the embedded trimer yields an ionization potential of 5.74+/-0.09 eV consistent with the value found in the gas phase. The asymmetrical form of the electron energy spectrum, which is broadened toward lower kinetic energies, is attributed to the influence of the matrix on the photoionization process. The lifetime of the excited state was measured in a two-color pump-probe experiment to be 5.7+/-0.6 ns.
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42
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Whitley HD, Huang P, Kwon Y, Whaley KB. Multiple solvation configurations around phthalocyanine in helium droplets. J Chem Phys 2007; 123:054307. [PMID: 16108639 DOI: 10.1063/1.1961532] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Recent measurements of the emission spectrum of phthalocyanine solvated in superfluid helium nanodroplets exhibit a constant 10.3 cm(-1) splitting of each emission line relative to the absorption spectrum. This splitting has been attributed to two distinct helium environments near the surface of the phthalocyanine molecule. Rigid-body path-integral Monte Carlo provides a means of investigating the origin of the splitting on a detailed microscopic level. Path-integral Monte Carlo simulations of 4He(N)-phthalocyanine at 0.625 K with N ranging from 24 to 150 show two distinct helium configurations. One configuration is commensurate with the molecular substrate and the other is a triangular lattice. We investigate the energetics of these two configurations and use a method for calculating electronic spectral shifts for aromatic molecule-rare-gas clusters due to dispersive interactions to estimate the spectral splitting that would arise from the two helium configurations seen for N=150. The results are in reasonable agreement with the experimentally measured splitting, supporting the existence of two distinct local helium environments near the surface of the molecule in the nanodroplets.
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Affiliation(s)
- Heather D Whitley
- Department of Chemistry and Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley, California 94720, USA.
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43
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Lindinger A, Toennies JP, Vilesov AF. Laser-induced fluorescence spectra of tetracene complexes with Ne, H2O, D2O inside He droplets. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.07.072] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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44
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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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45
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Lehnig R, Slenczka A. Spectroscopic investigation of the solvation of organic molecules in superfluid helium droplets. J Chem Phys 2005; 122:244317. [PMID: 16035767 DOI: 10.1063/1.1946739] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The spectroscopy of molecules doped into superfluid helium nanodroplets provides valuable information on the process of solvation in superfluid helium. In continuation of an earlier report on emission spectra of various phthalocyanines showing a splitting of all molecular transitions in the range of about 5-12 cm(-1), the emission spectra of tetracene, pentacene, and perylene in superfluid helium droplets are presented. The new spectra and the results obtained for the phthalocyanines are explained by an empirical model which accounts for the existence of different metastable configurations of a nonsuperfluid solvation layer around the guest molecule.
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Affiliation(s)
- R Lehnig
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Germany
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46
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Krasnokutski S, Rouillé G, Huisken F. Electronic spectroscopy of anthracene molecules trapped in helium nanodroplets. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.02.126] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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47
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Evidence of a shift between one- and two-photon processes associated with benzene trapped in helium nanodroplets. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2004.11.053] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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48
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Lehnig R, Slipchenko M, Kuma S, Momose T, Sartakov B, Vilesov A. Fine structure of the (S1←S0) band origins of phthalocyanine molecules in helium droplets. J Chem Phys 2004; 121:9396-405. [PMID: 15538859 DOI: 10.1063/1.1804945] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The laser-induced fluorescence (LIF) excitation spectra of free base phthalocyanine (Pc), Mg-Pc, and Zn-Pc molecules in superfluid helium droplets at T=0.38 K have been studied. The spectra reveal the rich vibronic structure of the S(1)<--S(0) electronic transitions. The band origins of the transitions consist of zero phonon lines accompanied by phonon wings, which originate from simultaneous electronic excitation of the molecule and excitation of the collective modes of the helium surrounding it. The phonon wings have discrete structures suggesting localization of some helium atoms in the neighborhood of the molecules. Zero phonon lines of Mg-Pc and Zn-Pc molecules are split into three components, which are separated by 0.2-0.4 cm(-1). Possible mechanism of splitting involves static or dynamic Jahn-Teller interaction of metal-phthalocyanine molecules in the twofold degenerate S(1)((1)E(u)) state with the helium shell.
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Affiliation(s)
- Rudolf Lehnig
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
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49
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Radcliffe P, Przystawik A, Diederich T, Döppner T, Tiggesbäumker J, Meiwes-Broer KH. Excited-state relaxation of Ag8 clusters embedded in helium droplets. PHYSICAL REVIEW LETTERS 2004; 92:173403. [PMID: 15169149 DOI: 10.1103/physrevlett.92.173403] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2003] [Indexed: 05/24/2023]
Abstract
Neutral silver clusters Ag(N) are grown in ultracold helium nanodroplets. By exploiting a strong absorption resonance recently found for Ag8, first photoelectron spectra of this neutral species are recorded. Variation of the laser photon energy reveals that direct vertical two-photon ionization is hindered by rapid relaxation into the lower edge of a long-living excited state manifold. The analysis of the dynamics gives a precise value of (6.89+/-0.09) eV for the vertical ionization potential of Ag8. The influence of the helium matrix on photoemission is discussed.
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Affiliation(s)
- Paul Radcliffe
- Fachbereich Physik, Universität Rostock, 18051 Rostock, Germany
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50
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Rouille G, Krasnokutski S, Huisken F, Henning T, Sukhorukov O, Staicu A. Ultraviolet spectroscopy of pyrene in a supersonic jet and in liquid helium droplets. J Chem Phys 2004; 120:6028-34. [PMID: 15267485 DOI: 10.1063/1.1651476] [Citation(s) in RCA: 32] [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 a series of experiments devoted to the study of polycyclic aromatic hydrocarbons for astrophysical applications, the S(2)<--S(0) transition of jet-cooled pyrene (C(16)H(10)) at 321 nm has been studied by an absorption technique for the first time. The spectra observed by cavity ring-down spectroscopy closely resemble the excitation spectra obtained earlier by laser-induced fluorescence (LIF) and show the same band clusters arising from the vibronic interaction of S(2) with S(1). We have also investigated pyrene when it was incorporated into 380 mK cold helium droplets. These spectra which were recorded employing LIF and molecular beam depletion spectroscopy are broadened and redshifted by 0.94 nm but retain the essential features of the gas phase spectra.
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Affiliation(s)
- Gael Rouille
- Max-Planck-Institut fur Astronomie, Konigstuhl 17, D-69117 Heidelberg, Germany
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