1
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Špirko V. Reduced Radial Curves of Diatomic Molecules. J Chem Theory Comput 2023; 19:7324-7332. [PMID: 37774238 PMCID: PMC10601484 DOI: 10.1021/acs.jctc.3c00622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Indexed: 10/01/2023]
Abstract
The prospect of using the concept of a universal reduced potential energy curve (RPC) for a broader class of radial molecular functions is explored by performing appropriate model calculations for the electric dipole moment functions of the hydrogen halides HF, HCl, and HBr. The reduced radial functions of the model systems, constructed from their best available theoretical approximants, coincide so closely that they can be used as few-parameter universal representations of functions available in the literature. Given the mathematical nature of the problem addressed here, the results are not limited to the functions studied but can be applied equally well to all radial molecular functions that have similar shapes, such as electric quadrupole moment and dipole polarizability functions.
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Affiliation(s)
- Vladimír Špirko
- Institute of Organic Chemistry
and Biochemistry, p.r.i., Czech Academy
of Sciences, Flemingovo nám. 2, 166 10 Prague 6, Czechia
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2
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Boninsegni M. The Solid Phase of 4He: A Monte Carlo Simulation Study. ENTROPY (BASEL, SWITZERLAND) 2023; 25:1114. [PMID: 37628144 PMCID: PMC10453513 DOI: 10.3390/e25081114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/21/2023] [Accepted: 07/21/2023] [Indexed: 08/27/2023]
Abstract
The thermodynamics of solid (hcp) 4He is studied theoretically by means of unbiased Monte Carlo simulations at finite temperature, in a wide range of density. This study complements and extends previous theoretical work, mainly by obtaining results at significantly lower temperatures (down to 60 mK) and for systems of greater size, by including in full the effect of quantum statistics, and by comparing estimates yielded by different pair potentials. All the main thermodynamic properties of the crystal, e.g., the kinetic energy per atom, are predicted to be essentially independent of temperature below ∼ 1 K. Quantum-mechanical exchanges are virtually non-existent in this system, even at the lowest temperature considered. However, effects of quantum statistics are detectable in the momentum distribution. Comparison with available measurements shows general agreement within the experimental uncertainties.
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Affiliation(s)
- Massimo Boninsegni
- Department of Physics, University of Alberta, Edmonton, AB T6G 2H5, Canada
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3
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Sesé LM. A Glimpse into Quantum Triplet Structures in Supercritical 3He. ENTROPY (BASEL, SWITZERLAND) 2023; 25:283. [PMID: 36832649 PMCID: PMC9955445 DOI: 10.3390/e25020283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/19/2023] [Accepted: 01/29/2023] [Indexed: 06/18/2023]
Abstract
A methodological study of triplet structures in quantum matter is presented. The focus is on helium-3 under supercritical conditions (4 < T/K < 9; 0.022 < ρN/Å-3 < 0.028), for which strong quantum diffraction effects dominate the behavior. Computational results for the triplet instantaneous structures are reported. Path integral Monte Carlo (PIMC) and several closures are utilized to obtain structure information in the real and the Fourier spaces. PIMC involves the fourth-order propagator and the SAPT2 pair interaction potential. The main triplet closures are: AV3, built as the average of the Kirkwood superposition and the Jackson-Feenberg convolution, and the Barrat-Hansen-Pastore variational approach. The results illustrate the main characteristics of the procedures employed by concentrating on the salient equilateral and isosceles features of the computed structures. Finally, the valuable interpretive role of closures in the triplet context is highlighted.
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Affiliation(s)
- Luis M Sesé
- Departamento de Ciencias y Técnicas Fisicoquímicas, Facultad de Ciencias, Universidad Nacional de Educación a Distancia (UNED), Avda. Esparta s/n, Las Rozas, 28232 Madrid, Spain
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4
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Ellis AM, Davies JA, Yurtsever E, Calvo F. Dimerization dynamics of carboxylic acids in helium nanodroplets. J Chem Phys 2022; 156:174304. [PMID: 35525638 DOI: 10.1063/5.0087957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dimerization of molecules in helium nanodroplets is known to preferentially yield structures of higher energy than the global energy minimum structure for a number of quite different monomers. Here, we explore dimerization in this environment using an atomistic model within statistically converged molecular dynamics (MD) trajectories, treating the solvent implicitly through the use of a thermostat, or more explicitly by embedding one monomer in a He100 cluster. The focus is on the two simplest carboxylic acids, formic and acetic, both of which have been studied experimentally. While the global minimum structure, which comprises two CO⋯HO hydrogen bonds, is predicted to be the most abundant dimer in the absence of the helium solvent, this is no longer the case once helium atoms are included. The simulations confirm the importance of kinetic trapping effects and also shed light on the occurrence of specific dynamical effects, leading to the occasional formation of high-energy structures away from minima, such as saddle configurations. Theoretically predicted infrared spectra, based on the MD statistics, are in good agreement with the experimental spectra.
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Affiliation(s)
- Andrew M Ellis
- School of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Julia A Davies
- School of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Ersin Yurtsever
- Department of Chemistry, Koç University, Rumelifeneri Yolu, Sariyer, 34450 Istanbul, Turkey
| | - Florent Calvo
- Université Grenoble Alpes, CNRS, LiPhy, F38000 Grenoble, France
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5
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Najjari B, Wang Z, Voitkiv AB. Probing the Helium Dimer by Relativistic Highly Charged Projectiles. PHYSICAL REVIEW LETTERS 2021; 127:203401. [PMID: 34860041 DOI: 10.1103/physrevlett.127.203401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 09/27/2021] [Indexed: 06/13/2023]
Abstract
We study the fragmentation of He_{2} dimers into He^{+} ions by relativistic highly charged projectiles. We demonstrate that the interaction between an ultrafast projectile with an extremely extended object-the helium dimer-possesses interesting features that are absent in collisions with "normal" molecules. We also show that such projectiles, due to their enormous interaction range, can accurately probe the ground state of the dimer and even be used for a determination of its binding energy.
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Affiliation(s)
- B Najjari
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Z Wang
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- Institute for Theoretical Physics I, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - A B Voitkiv
- Institute for Theoretical Physics I, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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6
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Bonhommeau DA. Zero-point averaged dynamics of Arn+He1000: Dopant-size influence on potential-energy surfaces, mass spectra and fragmentation patterns. Chem Phys 2021. [DOI: 10.1016/j.chemphys.2021.111307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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7
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Halberstadt N, Bonhommeau DA. Fragmentation dynamics of Ar 4He 1000 upon electron impact ionization: Competition between ion ejection and trapping. J Chem Phys 2020; 152:234305. [PMID: 32571060 DOI: 10.1063/5.0009363] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The fragmentation upon electron impact ionization of Ar4He1000 is investigated by means of mixed quantum-classical dynamics simulations. The Ar4 + dopant dynamics is described by a surface hopping method coupled with a diatomics-in-molecules model to properly take into account the multiple Ar4 + electronic surfaces and possible transitions between them. Helium atoms are treated individually using zero-point averaged dynamics, a method based on the building of an effective He-He potential. Fast electronic relaxation is observed from less than 2 ps to ∼30 ps, depending on initial conditions. The main fragments observed are Ar2 +Heq and Ar3 +Heq (q ≤ 1000), with a strong contribution of the bare Ar2 + ion, and neither Ar+ nor Ar+Heq fragments are found. The smaller fragments (q ≤ 50) are found to mostly come from ion ejection, whereas larger fragments (q > 500) originate from long-term ion trapping. Although the structure of the trapped Ar2 + ions is the same as in the gas phase, trapped Ar3 + and Ar4 + are rather slightly bound Ar2 +⋯Ar and Ar2 +⋯Ar⋯Ar structures (i.e., an Ar2 + core with one or two argon atoms roaming within the droplet). These loose structures can undergo geminate recombination and release Ar3 +Heq or Ar4 +Heq (q ≤ 50) in the gas phase and/or induce strong helium droplet evaporation. Finally, the translational energy of the fragment center of mass was found to be suitable to provide a clear signature of the broad variety of processes at play in our simulations.
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Affiliation(s)
| | - David A Bonhommeau
- Université de Reims Champagne Ardenne, CNRS, GSMA UMR 7331, 51097 Reims, France
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8
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Shcherbinin M, Westergaard FV, Hanif M, Krishnan SR, LaForge AC, Richter R, Pfeifer T, Mudrich M. Inelastic scattering of photoelectrons from He nanodroplets. J Chem Phys 2019; 150:044304. [PMID: 30709284 DOI: 10.1063/1.5074130] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
We present a detailed study of inelastic energy-loss collisions of photoelectrons emitted from He nanodroplets by tunable extreme ultraviolet (XUV) radiation. Using coincidence imaging detection of electrons and ions, we probe the lowest He droplet excited states up to the electron impact ionization threshold. We find significant signal contributions from photoelectrons emitted from free He atoms accompanying the He nanodroplet beam. Furthermore, signal contributions from photoionization and electron impact excitation/ionization occurring in pairs of nearest-neighbor atoms in the He droplets are detected. This work highlights the importance of inelastic electron scattering in the interaction of nanoparticles with XUV radiation.
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Affiliation(s)
- M Shcherbinin
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - F Vad Westergaard
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - M Hanif
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - S R Krishnan
- Department of Physics, Indian Institute of Technology, Madras, Chennai 600 036, India
| | - A C LaForge
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA
| | - R Richter
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - T Pfeifer
- Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
| | - M Mudrich
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
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9
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Kaiser A, Postler J, Ončák M, Kuhn M, Renzler M, Spieler S, Simpson M, Gatchell M, Beyer MK, Wester R, Gianturco FA, Scheier P. Isomeric Broadening of C 60+ Electronic Excitation in Helium Droplets: Experiments Meet Theory. J Phys Chem Lett 2018; 9:1237-1242. [PMID: 29470071 PMCID: PMC5857924 DOI: 10.1021/acs.jpclett.8b00150] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 02/22/2018] [Indexed: 05/13/2023]
Abstract
Helium is considered an almost ideal tagging atom for cold messenger spectroscopy experiments. Although helium is bound very weakly to the ionic molecule of interest, helium tags can lead to shifts and broadenings that we recorded near 963.5 nm in the electronic excitation spectrum of C60+ solvated with up to 100 helium atoms. Dedicated quantum calculations indicate that the inhomogeneous broadening is due to different binding energies of helium to the pentagonal and hexagonal faces of C60+, their dependence on the electronic state, and the numerous isomeric structures that become available for intermediate coverage. Similar isomeric effects can be expected for optical spectra of most larger molecules surrounded by nonabsorbing weakly bound solvent molecules, a situation encountered in many messenger-tagging spectroscopy experiments.
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Affiliation(s)
- Alexander Kaiser
- Institut für Ionenphysik und
Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
| | - Johannes Postler
- Institut für Ionenphysik und
Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
| | - Milan Ončák
- Institut für Ionenphysik und
Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
| | - Martin Kuhn
- Institut für Ionenphysik und
Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
| | - Michael Renzler
- Institut für Ionenphysik und
Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
| | - Steffen Spieler
- Institut für Ionenphysik und
Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
| | - Malcolm Simpson
- Institut für Ionenphysik und
Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
| | - Michael Gatchell
- Institut für Ionenphysik und
Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
| | - Martin K. Beyer
- Institut für Ionenphysik und
Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
| | - Roland Wester
- Institut für Ionenphysik und
Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
| | - Francesco A. Gianturco
- Institut für Ionenphysik und
Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
| | - Paul Scheier
- Institut für Ionenphysik und
Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
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10
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Bonhommeau DA. A practical law to predict the appearance sizes of multiply charged rare-gas and molecular clusters. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.07.068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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11
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Przybytek M, Cencek W, Jeziorski B, Szalewicz K. Pair Potential with Submillikelvin Uncertainties and Nonadiabatic Treatment of the Halo State of the Helium Dimer. PHYSICAL REVIEW LETTERS 2017; 119:123401. [PMID: 29341636 DOI: 10.1103/physrevlett.119.123401] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Indexed: 06/07/2023]
Abstract
The pair potential for helium is computed with accuracy improved by an order of magnitude relative to the best previous determination. For the well region, its uncertainties are now below 1 millikelvin. The main improvement is due to the use of explicitly correlated wave functions at the nonrelativistic Born-Oppenheimer (BO) level of theory. The diagonal BO and the relativistic corrections are obtained from large full configuration interaction calculations. Nonadiabatic perturbation theory is used to predict the properties of the halo state of the helium dimer. Its binding energy and the average value of the interatomic distance are found to be 138.9(5) neV and 47.13(8) Å. The binding energy agrees with its first experimental determination of 151.9(13.3) neV [Zeller et al., Proc. Natl. Acad. Sci. U.S.A. 113, 14651 (2016)PNASA60027-842410.1073/pnas.1610688113].
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Affiliation(s)
- Michał Przybytek
- Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Wojciech Cencek
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA
| | - Bogumił Jeziorski
- Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Krzysztof Szalewicz
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA
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12
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Chrysos M, Piel H. On the thermophysical and transport properties of 3He and 4He: A bubble interaction potential versus state of the art. J Chem Phys 2017; 147:034105. [DOI: 10.1063/1.4993222] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Michael Chrysos
- LUNAM Université, Université d’Angers, CNRS UMR 6200, Laboratoire MOLTECH-Anjou, 2 Blvd. Lavoisier, 49045 Angers,
France
| | - Henri Piel
- LUNAM Université, Université d’Angers, CNRS UMR 6200, Laboratoire MOLTECH-Anjou, 2 Blvd. Lavoisier, 49045 Angers,
France
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13
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14
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Chrysos M. Dirac bubble potential for He-He and inadequacies in the continuum: Comparing an analytic model with elastic collision experiments. J Chem Phys 2017; 146:024106. [PMID: 28088134 DOI: 10.1063/1.4973612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We focus on the long-pending issue of the inadequacy of the Dirac bubble potential model in the description of He-He interactions in the continuum [L. L. Lohr and S. M. Blinder, Int. J. Quantum Chem. 53, 413 (1995)]. We attribute this failure to the lack of a potential wall to mimic the onset of the repulsive interaction at close range separations. This observation offers the explanation to why this excessively simple model proves incapable of quantitatively reproducing previous experimental findings of glory scattering in He-He, although being notorious for its capability of reproducing several distinctive features of the atomic and isotopic helium dimers and trimers [L. L. Lohr and S. M. Blinder, Int. J. Quantum Chem. 90, 419 (2002)]. Here, we show that an infinitely high, energy-dependent potential wall of properly calculated thickness rc(E) taken as a supplement to the Dirac bubble potential suffices for agreement with variable-energy elastic collision cross section experiments for 4He-4He, 3He-4He, and 3He-3He [R. Feltgen et al., J. Chem. Phys. 76, 2360 (1982)]. In the very low energy regime, consistency is found between the Dirac bubble potential (to which our extended model is shown to reduce) and cold collision experiments [J. C. Mester et al., Phys. Rev. Lett. 71, 1343 (1993)]; this consistency, which in this regime lends credence to the Dirac bubble potential, was never noticed by its authors. The revised model being still analytic is of high didactical value while expected to increase in predictive power relative to other appraisals.
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Affiliation(s)
- Michael Chrysos
- LUNAM Université, Université d'Angers, CNRS UMR 6200, Laboratoire MOLTECH-Anjou, 2 Bd Lavoisier, 49045 Angers, France
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15
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Zeller S, Kunitski M, Voigtsberger J, Kalinin A, Schottelius A, Schober C, Waitz M, Sann H, Hartung A, Bauer T, Pitzer M, Trinter F, Goihl C, Janke C, Richter M, Kastirke G, Weller M, Czasch A, Kitzler M, Braune M, Grisenti RE, Schöllkopf W, Schmidt LPH, Schöffler MS, Williams JB, Jahnke T, Dörner R. Imaging the He2 quantum halo state using a free electron laser. Proc Natl Acad Sci U S A 2016; 113:14651-14655. [PMID: 27930299 PMCID: PMC5187706 DOI: 10.1073/pnas.1610688113] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Quantum tunneling is a ubiquitous phenomenon in nature and crucial for many technological applications. It allows quantum particles to reach regions in space which are energetically not accessible according to classical mechanics. In this "tunneling region," the particle density is known to decay exponentially. This behavior is universal across all energy scales from nuclear physics to chemistry and solid state systems. Although typically only a small fraction of a particle wavefunction extends into the tunneling region, we present here an extreme quantum system: a gigantic molecule consisting of two helium atoms, with an 80% probability that its two nuclei will be found in this classical forbidden region. This circumstance allows us to directly image the exponentially decaying density of a tunneling particle, which we achieved for over two orders of magnitude. Imaging a tunneling particle shows one of the few features of our world that is truly universal: the probability to find one of the constituents of bound matter far away is never zero but decreases exponentially. The results were obtained by Coulomb explosion imaging using a free electron laser and furthermore yielded He2's binding energy of [Formula: see text] neV, which is in agreement with most recent calculations.
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Affiliation(s)
- Stefan Zeller
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany;
| | - Maksim Kunitski
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Jörg Voigtsberger
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Anton Kalinin
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | | | - Carl Schober
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Markus Waitz
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Hendrik Sann
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Alexander Hartung
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Tobias Bauer
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Martin Pitzer
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Florian Trinter
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Christoph Goihl
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Christian Janke
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Martin Richter
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Gregor Kastirke
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Miriam Weller
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Achim Czasch
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Markus Kitzler
- Photonics Institute, Vienna University of Technology, 1040 Vienna, Austria
| | - Markus Braune
- Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Robert E Grisenti
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
- GSI Helmholtz Centre for Heavy Ion Research, 64291 Darmstadt, Germany
| | - Wieland Schöllkopf
- Department of Molecular Physics, Fritz-Haber-Institut, 14195 Berlin, Germany
| | - Lothar Ph H Schmidt
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Markus S Schöffler
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | | | - Till Jahnke
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Reinhard Dörner
- Institut für Kernphysik, Goethe-Universität Frankfurt, 60438 Frankfurt, Germany;
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16
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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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17
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Sharipov F, Benites VJ. Transport coefficients of helium-argon mixture based on ab initio potential. J Chem Phys 2015; 143:154104. [PMID: 26493894 DOI: 10.1063/1.4933327] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The viscosity, thermal conductivity, diffusion coefficient, and thermal diffusion factor of helium-argon mixtures are calculated for a wide range of temperature and for various mole fractions up to the 12th order of the Sonine polynomial expansion with an ab initio intermolecular potential. The calculated values for these transport coefficients are compared with other data available in the open literature. The comparison shows that the obtained transport coefficients of helium-argon mixture have the best accuracy for the moment.
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Affiliation(s)
- Felix Sharipov
- Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, Curitiba 81531-990, Brazil
| | - Victor J Benites
- Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, Curitiba 81531-990, Brazil
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18
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Shirkov L, Makarewicz J. Does DFT-SAPT method provide spectroscopic accuracy? J Chem Phys 2015; 142:064102. [DOI: 10.1063/1.4907204] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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19
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Calvo F. Coating Polycyclic Aromatic Hydrocarbon Cations with Helium Clusters: Snowballs and Slush. J Phys Chem A 2014; 119:5959-70. [DOI: 10.1021/jp510799h] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Florent Calvo
- University of Grenoble Alpes, LIPHY, F-38000 Grenoble, France and
- CNRS, LIPHY, F-38000 Grenoble, France
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20
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Hashemi FS, Yaghoobi F. Transport Properties of Simple Fluids from the Soft-Core Double Yukawa Potential. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200500152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Buchta D, Krishnan SR, Brauer NB, Drabbels M, O’Keeffe P, Devetta M, Di Fraia M, Callegari C, Richter R, Coreno M, Prince KC, Stienkemeier F, Ullrich J, Moshammer R, Mudrich M. Extreme ultraviolet ionization of pure He nanodroplets: Mass-correlated photoelectron imaging, Penning ionization, and electron energy-loss spectra. J Chem Phys 2013; 139:084301. [DOI: 10.1063/1.4818531] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [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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Sesé LM. Path integral Monte Carlo study of quantum-hard sphere solids. J Chem Phys 2013; 139:044502. [DOI: 10.1063/1.4813635] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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23
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Cencek W, Przybytek M, Komasa J, Mehl JB, Jeziorski B, Szalewicz K. Effects of adiabatic, relativistic, and quantum electrodynamics interactions on the pair potential and thermophysical properties of helium. J Chem Phys 2012; 136:224303. [DOI: 10.1063/1.4712218] [Citation(s) in RCA: 209] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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24
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Przybytek M, Jeziorski B, Cencek W, Komasa J, Mehl JB, Szalewicz K. Onset of Casimir-Polder retardation in a long-range molecular quantum state. PHYSICAL REVIEW LETTERS 2012; 108:183201. [PMID: 22681072 DOI: 10.1103/physrevlett.108.183201] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Indexed: 06/01/2023]
Abstract
Two 4He atoms form a diatomic molecule with a significant vibrational wave function amplitude at interatomic separations R>100 Å, where the retardation switches the London R(-6) decay of the potential to the Casimir-Polder R(-7) form. It has been assumed that this effect of retardation on the long-range part of the potential is responsible for the 2 Å (4%) increase of the bond length <R> of 4He2. We show that <R> is, unexpectedly, insensitive to the potential at R>20 Å and its increase is due to quantum electrodynamics effects computed by us from expressions valid at short R--beyond the validity range of Casimir-Polder theory--that seamlessly extend this theory to distances relevant for properties of long molecules.
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Affiliation(s)
- Michał Przybytek
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
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25
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Roudnev V, Cavagnero M. Approaching universality in weakly bound three-body systems. PHYSICAL REVIEW LETTERS 2012; 108:110402. [PMID: 22540442 DOI: 10.1103/physrevlett.108.110402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Indexed: 05/31/2023]
Abstract
Atom-dimer scattering below the three-body breakup threshold is studied for a system of three identical bosons. The atom-dimer scattering length and the energy of the most weakly bound three-body state are shown to be strongly correlated. An appropriate rescaling of the observables reveals the subtlety of the correlation and serves to identify universal trends in the unitary limit of divergent two-body scattering length. The correlation provides a new quantitative measure of the degree of universality in three-body systems with short-ranged interactions, as well as a consistency check of effective field theories and other theoretical models.
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Affiliation(s)
- Vladimir Roudnev
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055, USA
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26
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Kullie O, Saue T. Range-separated density functional theory: A 4-component relativistic study of the rare gas dimers He2, Ne2, Ar2, Kr2, Xe2, Rn2 and Uuo2. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2011.06.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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27
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Ma Z, Cai W, Shao X. Impact of different potentials on the structures and energies of clusters. J Comput Chem 2011; 32:3075-80. [DOI: 10.1002/jcc.21891] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Revised: 06/17/2011] [Accepted: 06/22/2011] [Indexed: 12/12/2022]
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28
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Sheng XW, Mentel L, Gritsenko OV, Baerends EJ. Counterpoise correction is not useful for short and Van der Waals distances but may be useful at long range. J Comput Chem 2011; 32:2896-901. [PMID: 21735451 DOI: 10.1002/jcc.21872] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 05/05/2011] [Accepted: 05/25/2011] [Indexed: 11/12/2022]
Abstract
This article investigates the errors in supermolecule calculations for the helium dimer. In a full CI calculation, there are two errors. One is the basis set superposition error (BSSE), the other is the basis set convergence error (BSCE). Both of the errors arise from the incompleteness of the basis set. These two errors make opposite contributions to the interaction energies. The BSCE is by far the largest error in the short range and larger than (but much closer to) BSSE around the Van der Waals minimum. Only at the long range, the BSSE becomes the larger error. The BSCE and BSSE largely cancel each other over the Van der Waals well. Accordingly, it may be recommended to not include the BSSE for the calculation of the potential energy curve from short distance till well beyond the Van der Waals minimum, but it may be recommended to include the BSSE correction if an accurate tail behavior is required. Only if the calculation has used a very large basis set, one can refrain from including the counterpoise correction in the full potential range. These results are based on full CI calculations with the aug-cc-pVXZ (X = D, T, Q, 5) basis sets.
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Affiliation(s)
- Xiao Wei Sheng
- The Institute of Atomic and Molecular physics, Sichuan University, Chengdu, Sichuan 610065, China
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29
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Vehmanen E, Ghazarian V, Sams C, Khachatryan I, Eloranta J, Apkarian VA. Injection of atoms and molecules in a superfluid helium fountain: Cu and Cu2He(n) (n = 1, ..., ∞). J Phys Chem A 2011; 115:7077-88. [PMID: 21449544 DOI: 10.1021/jp1123986] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We introduce an experimental platform designed around a thermomechanical helium fountain, which is aimed at investigating spectroscopy and dynamics of atoms and molecules in the superfluid and at its vapor interface. Laser ablation of copper, efficient cooling and transport of Cu and Cu(2) through helium vapor (1.5 K < T < 20 K), formation of linear and T-shaped Cu(2)-He complexes, and their continuous evolution into large Cu(2)-He(n) clusters and droplets are among the processes that are illustrated. Reflection is the dominant quantum scattering channel of translationally cold copper atoms (T = 1.7 K) at the fountain interface. Cu(2) dimers mainly travel through the fountain unimpeded. However, the conditions of fountain flow and transport of molecules can be controlled to demonstrate injection and, in particular, injection into a nondivergent columnar fountain with a plug velocity of about 1 m/s. The experimental observables are interpreted with the aid of bosonic density functional theory calculations and ab initio interaction potentials.
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Affiliation(s)
- Esa Vehmanen
- Department of Chemistry, Nanoscience Center, University of Jyväskylä, P.O. Box 35, FIN 40014, Finland
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30
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Oleksy K, Karlický F, Kalus R. Structures and energetics of helium cluster cations: equilibrium geometries revisited through the genetic algorithm approach. J Chem Phys 2011; 133:164314. [PMID: 21033795 DOI: 10.1063/1.3489346] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Equilibrium geometries and dissociation energies of He(N)(+) clusters have been calculated for N=3-35 using an extended genetic algorithm approach and a semiempirical model of intracluster interactions [P. J. Knowles, J. N. Murrell, and E. J. Hodge, Mol. Phys. 85, 243 (1995)]. A general aufbau principle is formulated for both ionic cores and neutral solvation shells, and the results are thoroughly compared with other theoretical data available for helium cluster cations in literature.
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Affiliation(s)
- Karel Oleksy
- Department of Physics, Faculty of Science, University of Ostrava, 30. dubna 22, Ostrava 701 03, Czech Republic.
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31
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Bich E, Hellmann R, Vogel E. Ab initiopotential energy curve for the helium atom pair and thermophysical properties of the dilute helium gas. II. Thermophysical standard values for low-density helium. Mol Phys 2010. [DOI: 10.1080/00268970701744584] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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32
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Hellmann R, Bich E, Vogel E. Ab initiopotential energy curve for the helium atom pair and thermophysical properties of dilute helium gas. I. Helium–helium interatomic potential. Mol Phys 2010. [DOI: 10.1080/00268970701730096] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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33
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Szalewicz K, Jeziorski B. Explicitly-correlated Gaussian geminals in electronic structure calculations. Mol Phys 2010. [DOI: 10.1080/00268976.2010.522206] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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34
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35
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Tong XF, Yang CL, An YP, Wang MS, Ma XG, Wang DH. Theoretical characteristics of the bound states of M-X complexes (M=Cu, Ag, and Au, and X=He, Ne, and Ar). J Chem Phys 2009; 131:244304. [DOI: 10.1063/1.3274815] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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36
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Amat MA, Arienti M, Fonoberov VA, Kevrekidis IG, Maroudas D. Coarse molecular-dynamics analysis of an order-to-disorder transformation of a krypton monolayer on graphite. J Chem Phys 2008; 129:184106. [DOI: 10.1063/1.3006427] [Citation(s) in RCA: 5] [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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37
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Sesé LM. Computational study of the structures of gaseous helium-3 at low temperature. J Phys Chem B 2008; 112:10241-54. [PMID: 18651763 DOI: 10.1021/jp802542u] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A computational study of gaseous helium-3 at T=5.23 K, for number densities rho N<0.0021 A(-3), analyzing the different pair and triplet structures in both the r and the k spaces, is presented. Structures in r space (i.e., instantaneous, total continuous linear response, and centroids) are determined via path-integral Monte Carlo simulations in the canonical ensemble by utilizing the Aziz-Slaman and the SAPT2 interatomic potentials. Additional results obtained with the application of two closures for triplets in r space, the Kirkwood superposition approximation and the Jackson-Feenberg convolution, are also reported. Besides, an analysis of the nonsuitability of quantum hard spheres for describing this system is included. The pair structures in k space are fixed via Ornstein-Zernike schemes appropriate for dealing with quantum diffraction effects in fluids. The effect on the quality of the computed isothermal compressibilities brought about by increasing the sample size in the simulations and by the subsequent application of a grand ensemble correction to the asymptotic behavior of the canonical pair radial correlation functions is also investigated. Furthermore, it is demonstrated analytically that the methods of classical statistical mechanics for dealing with the higher-order direct correlation functions remain fully valid for studying the higher-order correlations of path-integral centroids. By taking advantage of this result, the triplet structure factors for the centroid (also for the instantaneous) correlations are computed by following a number of distinct closures and methods that involve triplet direct correlation functions. The latter computations are intended to explore an alternative scheme to the very expensive fixing of triplet structure factors through direct path integral simulations, an alternative which is expected to yield the main features of these triplet quantities for this gas. Comparison with experiment is made wherever possible, and the results presented allow one to explain the substantial structural features existing in gaseous helium-3.
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Affiliation(s)
- Luis M Sesé
- Departamento de Ciencias y Técnicas Fisicoquímicas, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, Madrid, Spain.
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38
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Tong X, Černý J, Müller-Dethlefs K. Effect of Noncovalent Interactions on the n-Butylbenzene···Ar Cluster Studied by Mass Analyzed Threshold Ionization Spectroscopy and ab initio Computations. J Phys Chem A 2008; 112:5872-7. [DOI: 10.1021/jp710998m] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Xin Tong
- The Photon Science Institute, Alan Turing Building, the School of Chemistry, and the School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, U.K
| | - Jiří Černý
- The Photon Science Institute, Alan Turing Building, the School of Chemistry, and the School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, U.K
| | - Klaus Müller-Dethlefs
- The Photon Science Institute, Alan Turing Building, the School of Chemistry, and the School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, U.K
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39
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Przybytek M, Jeziorski B. Higher dispersion coefficients for the interaction of helium atoms. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.05.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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40
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Bonhommeau D, Lewerenz M, Halberstadt N. Fragmentation of ionized doped helium nanodroplets: theoretical evidence for a dopant ejection mechanism. J Chem Phys 2008; 128:054302. [PMID: 18266445 DOI: 10.1063/1.2823101] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report a theoretical study of the effect induced by a helium nanodroplet environment on the fragmentation dynamics of a dopant. The dopant is an ionized neon cluster Ne(n) (+) (n=4-6) surrounded by a helium nanodroplet composed of 100 atoms. A newly designed mixed quantum/classical approach is used to take into account both the large helium cluster zero-point energy due to the light mass of the helium atoms and all the nonadiabatic couplings between the Ne(n) (+) potential-energy surfaces. The results reveal that the intermediate ionic dopant can be ejected from the droplet, possibly with some helium atoms still attached, thereby reducing the cooling power of the droplet. Energy relaxation by helium atom evaporation and dissociation, the other mechanism which has been used in most interpretations of doped helium cluster dynamics, also exhibits new features. The kinetic energy distribution of the neutral monomer fragments can be fitted to the sum of two Boltzmann distributions, one with a low kinetic energy and the other with a higher kinetic energy. This indicates that cooling by helium atom evaporation is more efficient than was believed so far, as suggested by recent experiments. The results also reveal the predominance of Ne(2) (+) and He(q)Ne(2) (+) fragments and the absence of bare Ne(+) fragments, in agreement with available experimental data (obtained for larger helium nanodroplets). Moreover, the abundance in fragments with a trimeric neon core is found to increase with the increase in dopant size. Most of the fragmentation is achieved within 10 ps and the only subsequent dynamical process is the relaxation of hot intermediate He(q)Ne(2) (+) species to Ne(2) (+) by helium atom evaporation. The dependence of the ionic fragment distribution on the parent ion electronic state reached by ionization is also investigated. It reveals that He(q)Ne(+) fragments are produced only from the highest electronic state, whereas He(q)Ne(2) (+) fragments originate from all the electronic states. Surprisingly, the highest electronic states also lead to fragments that still contain the original ionic dopant species. A mechanism is conjectured to explain this fragmentation inhibition.
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Affiliation(s)
- D Bonhommeau
- University of Minnesota, 207 Pleasant Street S.E., 230 Smith Hall, Minneapolis, Minnesota 55455-0431, USA
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41
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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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42
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Patkowski K, Cencek W, Jankowski P, Szalewicz K, Mehl JB, Garberoglio G, Harvey AH. Potential energy surface for interactions between two hydrogen molecules. J Chem Phys 2008; 129:094304. [DOI: 10.1063/1.2975220] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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43
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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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44
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Jeziorska M, Cencek W, Patkowski K, Jeziorski B, Szalewicz K. Pair potential for helium from symmetry-adapted perturbation theory calculations and from supermolecular data. J Chem Phys 2007; 127:124303. [PMID: 17902899 DOI: 10.1063/1.2770721] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Symmetry-adapted perturbation theory (SAPT) was applied to the helium dimer for interatomic separations R from 3 to 12 bohrs. The first-order interaction energy and the bulk of the second-order contribution were obtained using Gaussian geminal basis sets and are converged to about 0.1 mK near the minimum and for larger R. The remaining second-order contributions available in the SAPT suite of codes were computed using very large orbital basis sets, up to septuple-zeta quality, augmented by diffuse and midbond functions. The accuracy reached at this level was better than 1 mK in the same region. All the remaining components of the interaction energy were computed using the full configuration interaction method in bases up to sextuple-zeta quality. The latter components, although contributing only 1% near the minimum, have the largest uncertainty of about 10 mK in this region. The total interaction energy at R=5.6 bohrs is -11.000+/-0.011 K. For R< or =6.5 bohrs, the supermolecular (SM) interaction energies computed by us recently turned out to be slightly more accurate. Therefore, we have combined the SM results for R< or =6.5 bohrs with the SAPT results from 7.0 to 12 bohrs to fit analytic functions for the potential and for its error bars. The potential fit uses the best available van der Waals constants C(6) through C(16), including C(11), C(13), and C(15), and is believed to be the best current representation of the Born-Oppenheimer (BO) potential for helium. Using these fits, we found that the BO potential for the helium dimer exhibits the well depth D(e)=11.006+/-0.004 K, the equilibrium distance R(e)=5.608+/-0.012 bohrs, and supports one bound state for (4)He(2) with the dissociation energy D(0)=1.73+/-0.04 mK, and the average interatomic separation R=45.6+/-0.5 A.
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Affiliation(s)
- Małgorzata Jeziorska
- Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
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45
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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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46
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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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47
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Peterka DS, Kim JH, Wang CC, Poisson L, Neumark DM. Photoionization Dynamics in Pure Helium Droplets. J Phys Chem A 2007; 111:7449-59. [PMID: 17571863 DOI: 10.1021/jp0710032] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photoionization and photoelectron spectroscopy of pure He droplets were investigated at photon energies between 24.6 eV (the ionization energy of He) and 28.0 eV. Time-of-flight mass spectra and photoelectron images were obtained at a series of molecular beam source temperatures and pressures to assess the effect of droplet size on the photoionization dynamics. At source temperatures below 16 K, where there is significant production of clusters with more than 10(4) atoms, the photoelectron images are dominated by fast electrons produced via direct ionization, with a small contribution from very slow electrons with kinetic energies below 1 meV arising from an indirect mechanism. The fast photoelectrons from the droplets have as much as 0.5 eV more kinetic energy than those from atomic He at the same photon energy. This result is interpreted and simulated within the context of a "dimer model", in which one assumes vertical ionization from two nearest-neighbor He atoms to the attractive region of the He2+ potential energy curve. Possible mechanisms for the slow electrons, which were also seen at energies below IE(He), are discussed, including vibrational autoionizaton of Rydberg states comprising an electron weakly bound to the surface of a large HeN+ core.
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Affiliation(s)
- Darcy S Peterka
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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48
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Patkowski K, Cencek W, Jeziorska M, Jeziorski B, Szalewicz K. Accurate Pair Interaction Energies for Helium from Supermolecular Gaussian Geminal Calculations. J Phys Chem A 2007; 111:7611-23. [PMID: 17550239 DOI: 10.1021/jp071437x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nonrelativistic clamped-nuclei pair interaction energy for ground-state helium atoms has been computed for 12 interatomic separations ranging from 3.0 to 9.0 bohr. The calculations applied the supermolecular approach. The major part of the interaction energy was obtained using the Gaussian geminal implementation of the coupled-cluster theory with double excitations (CCD). Relatively small contributions from single, triple, and quadruple excitations were subsequently included employing the conventional orbital coupled-cluster method with single, double, and noniterative triple excitations [CCSD(T)] and the full configuration interaction (FCI) method. For three distances, the single-excitation contribution was taken from literature Gaussian-geminal calculations at the CCSD level. The orbital CCSD(T) and FCI calculations used very large basis sets, up to doubly augmented septuple- and sextuple-zeta size, respectively, and were followed by extrapolations to the complete basis set limits. The accuracy of the total interaction energies has been estimated to be about 3 mK or 0.03% at the minimum of the potential well. For the attractive part of the well, the relative errors remain consistently smaller than 0.03%. In the repulsive part, the accuracy is even better, except, of course, for the region where the potential goes through zero. For interatomic separations smaller than 4.0 bohr, the relative errors do not exceed 0.01%. Such uncertainties are significantly smaller than the expected values of the relativistic and diagonal Born-Oppenheimer contributions to the potential.
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Affiliation(s)
- Konrad Patkowski
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA
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49
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Belashchenko DK. The simulation of metallic hydrogen-helium solutions under the conditions of internal Jupiter regions. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2006. [DOI: 10.1134/s0036024406130061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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50
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Pachucki K, Komasa J. Radiative correction to the helium dimer interaction energy. J Chem Phys 2006; 124:64308. [PMID: 16483208 DOI: 10.1063/1.2166017] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The leading-order radiative correction to the helium-helium interaction energy at the equilibrium internuclear distance has been calculated for the first time. The result is -1.27(2) mK. The calculations were performed using a new technique of evaluating expectation values of singular operators in connection with the most accurate wave functions of He(2) available today-the exponentially correlated Gaussian functions.
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