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Schmidt M, Roy PN. On the accuracy and efficiency of different methods to calculate Raman vibrational shifts of parahydrogen clusters. J Chem Phys 2022; 156:084102. [DOI: 10.1063/5.0076403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Raman vibrational frequency shifts of pure parahydrogen and orthodeuterium clusters of sizes N = 4–9 are calculated using the Langevin equation path integral ground state method. The shifts are calculated using three different methods; the results obtained from each are compared to experiment and variance properties are assessed. The first method requires the direct calculation of energies from two simulations: one when the cluster is in the v = 0 vibrational state and one when the cluster has v = 1 total quantum of vibration. The shift is directly calculated from the difference in those two energies. The second method requires only a v = 0 simulation to be performed. The ground state energy is calculated as usual and the excited state energy is calculated by using the distribution of the v = 0 simulation and the ratio of the density matrices between the v = 1 state and the v = 0 state. The shift is calculated from the difference in those two energies. These first two are both exact methods. The final method is based on perturbation theory where the shift is calculated by averaging the pairwise difference potential over the pair distribution function. However, this is an approximate approach. It is found that for large enough system sizes, despite the approximations, the perturbation theory method has the strongest balance between accuracy and precision when weighing against computational cost.
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Affiliation(s)
- Matthew Schmidt
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Pierre-Nicholas Roy
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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2
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Brieuc F, Schran C, Uhl F, Forbert H, Marx D. Converged quantum simulations of reactive solutes in superfluid helium: The Bochum perspective. J Chem Phys 2020; 152:210901. [DOI: 10.1063/5.0008309] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Fabien Brieuc
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Christoph Schran
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Felix Uhl
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Harald Forbert
- Center for Solvation Science ZEMOS, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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Faulkner T, Miller I, Raston PL. Quantum cascade laser spectroscopy of OCS isotopologues in 4He nanodroplets: A test of adiabatic following for a heavy rotor. J Chem Phys 2018; 148:044308. [DOI: 10.1063/1.5009908] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ty Faulkner
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia 22807, USA
| | - Isaac Miller
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia 22807, USA
| | - Paul L. Raston
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia 22807, USA
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Farrelly D, Iñarrea M, Lanchares V, Salas JP. Lieb-Liniger-like model of quantum solvation in CO-(4)HeN clusters. J Chem Phys 2016; 144:204301. [PMID: 27250300 DOI: 10.1063/1.4949537] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Small (4)He clusters doped with various molecules allow for the study of "quantum solvation" as a function of cluster size. A peculiarity of quantum solvation is that, as the number of (4)He atoms is increased from N = 1, the solvent appears to decouple from the molecule which, in turn, appears to undergo free rotation. This is generally taken to signify the onset of "microscopic superfluidity." Currently, little is known about the quantum mechanics of the decoupling mechanism, mainly because the system is a quantum (N + 1)-body problem in three dimensions which makes computations difficult. Here, a one-dimensional model is studied in which the (4)He atoms are confined to revolve on a ring and encircle a rotating CO molecule. The Lanczos algorithm is used to investigate the eigenvalue spectrum as the number of (4)He atoms is varied. Substantial solvent decoupling is observed for as few as N = 5 (4)He atoms. Examination of the Hamiltonian matrix, which has an almost block diagonal structure, reveals increasingly weak inter-block (solvent-molecule) coupling as the number of (4)He atoms is increased. In the absence of a dopant molecule the system is similar to a Lieb-Liniger (LL) gas and we find a relatively rapid transition to the LL limit as N is increased. In essence, the molecule initially-for very small N-provides a central, if relatively weak, attraction to organize the cluster; as more (4)He atoms are added, the repulsive interactions between the identical bosons start to dominate as the solvation ring (shell) becomes more crowded which causes the molecule to start to decouple. For low N, the molecule pins the atoms in place relative to itself; as N increases the atom-atom repulsion starts to dominate the Hamiltonian and the molecule decouples. We conclude that, while the notion of superfluidity is a useful and correct description of the decoupling process, a molecular viewpoint provides complementary insights into the quantum mechanism of the transition from a molecular cluster to a quantum solvated molecule.
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Affiliation(s)
- D Farrelly
- Departamento de Matemáticas y Computación, Universidad de La Rioja, 26006 Logroño, Spain
| | - M Iñarrea
- Área de Física Aplicada, Universidad de La Rioja, 26006 Logroño, Spain
| | - V Lanchares
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA
| | - J P Salas
- Área de Física Aplicada, Universidad de La Rioja, 26006 Logroño, Spain
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Rodríguez-Cantano R, González-Lezana T, Villarreal P. Path integral Monte Carlo investigations on doped helium clusters. INT REV PHYS CHEM 2016. [DOI: 10.1080/0144235x.2015.1132595] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Wang L, Xie D, Le Roy RJ, Roy PN. A new four-dimensional ab initio potential energy surface for N2O-He and vibrational band origin shifts for the N2O-He(N) clusters with N = 1-40. J Chem Phys 2012; 137:104311. [PMID: 22979863 DOI: 10.1063/1.4749248] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A new four-dimensional ab initio potential energy surface for N(2)O-He is constructed at the CCSD(T) level with an aug-cc-pVQZ basis set together with bond functions. The vibrational coordinates Q(1) and Q(3) of N(2)O are explicitly included, due to the strong coupling between the symmetric and asymmetric stretches of N(2)O. A global potential energy surface is obtained by fitting the original potential points to a four-dimensional Morse∕long range (MLR) analytical form. In the fitting, the ab initio noise in the long range region of the potential is smoothed over by theoretically fixed long range parameters. Two-dimensional intermolecular potentials for both the ground and the excited υ(3) states of N(2)O are then constructed by vibrationally averaging the four-dimensional potential. Based on the two-dimensional potentials, we use the path integral Monte Carlo algorithm to calculate the vibrational band origin shifts for the N(2)O-He(N) clusters using a first order perturbation theory estimate. The calculated shifts agree reasonably well with the experimental values and reproduce the evolution tendency from dimer to large clusters.
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Affiliation(s)
- Lecheng Wang
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
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Wang L, Xie D. Finite temperature path integral Monte Carlo simulations of structural and dynamical properties of ArN−CO2 clusters. J Chem Phys 2012; 137:074308. [DOI: 10.1063/1.4746941] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Affiliation(s)
- Brian M. Austin
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, United States
| | - Dmitry Yu. Zubarev
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, United States
| | - William A. Lester
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Wang LC, Xie DQ. Simulated Annealing Study on Structures and Energetics of CO2 in Argon Clusters. CHINESE J CHEM PHYS 2011. [DOI: 10.1088/1674-0068/24/05/620-624] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Luo D, Zhang N, Hong S, Wu H, Liu Z. Complexes in the photocatalytic reaction of CO(2) and H(2)O: theoretical studies. Int J Mol Sci 2010; 11:2792-804. [PMID: 21152274 PMCID: PMC2996739 DOI: 10.3390/ijms11082792] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 07/16/2010] [Accepted: 07/18/2010] [Indexed: 11/16/2022] Open
Abstract
Complexes (H2O/CO2, e–(H2O/CO2) and h+–(H2O/CO2)) in the reaction system of CO2 photoreduction with H2O were researched by B3LYP and MP2 methods along with natural bond orbital (NBO) analysis. Geometries of these complexes were optimized and frequencies analysis performed. H2O/CO2 captured photo-induced electron and hole produced e–(H2O/CO2) and h+–(H2O/CO2), respectively. The results revealed that CO2 and H2O molecules could be activated by the photo-induced electrons and holes, and each of these complexes possessed two isomers. Due to the effect of photo-induced electrons, the bond length of C=O and H-O were lengthened, while H-O bonds were shortened, influenced by holes. The infrared (IR) adsorption frequencies of these complexes were different from that of CO2 and H2O, which might be attributed to the synergistic effect and which could not be captured experimentally.
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Affiliation(s)
- Dongmei Luo
- Department of Chemistry, Nanchang University, Nanchang 330031, China; E-Mails: (D.L.); (S.H.); (H.W.); (Z.L.)
- Department of Chemistry, QiqihaerUniversity, Qiqihaer 161006, China
| | - Ning Zhang
- Department of Chemistry, Nanchang University, Nanchang 330031, China; E-Mails: (D.L.); (S.H.); (H.W.); (Z.L.)
- *Author to whom correspondence should be addressed; E-Mail: ; Tel.: +86-791-3969-332; Fax: +86-791-3969-338
| | - Sanguo Hong
- Department of Chemistry, Nanchang University, Nanchang 330031, China; E-Mails: (D.L.); (S.H.); (H.W.); (Z.L.)
| | - Huanwen Wu
- Department of Chemistry, Nanchang University, Nanchang 330031, China; E-Mails: (D.L.); (S.H.); (H.W.); (Z.L.)
| | - Zhihua Liu
- Department of Chemistry, Nanchang University, Nanchang 330031, China; E-Mails: (D.L.); (S.H.); (H.W.); (Z.L.)
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Raston PL, Xu Y, Jäger W, Potapov AV, Surin LA, Dumesh BS, Schlemmer S. Rotational study of carbon monoxide isotopologues in small 4He clusters. Phys Chem Chem Phys 2010; 12:8260-7. [DOI: 10.1039/c0cp00193g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Li H, Blinov N, Roy PN, Le Roy RJ. Path-integral Monte Carlo simulation of ν3 vibrational shifts for CO2 in (He)n clusters critically tests the He–CO2 potential energy surface. J Chem Phys 2009; 130:144305. [DOI: 10.1063/1.3109897] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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de Lara-Castells MP, Villarreal P, Delgado-Barrio G, Mitrushchenkov AO. An optimized full-configuration-interaction nuclear orbital approach to a “hard-core” interaction problem: Application to ([sup 3]He)[sub N]–Cl[sub 2](B) clusters (N≤4). J Chem Phys 2009; 131:194101. [DOI: 10.1063/1.3263016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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