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Zúñiga J, Bastida A, Requena A, Cerezo J. Ab Initio Partition Functions and Thermodynamic Quantities for the Molecular Hydrogen Isotopologues. J Phys Chem A 2021; 125:9226-9241. [PMID: 34613734 PMCID: PMC8543445 DOI: 10.1021/acs.jpca.1c06468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/23/2021] [Indexed: 11/29/2022]
Abstract
In this work, we calculate the partition functions and thermodynamic quantities of molecular hydrogen isotopologues using the rovibrational energy levels provided by the highly accurate ab initio adiabatic potential energy functions recently determined by Pachucki and Komasa (Pachucki, K.; Komasa, J. J. Chem. Phys. 2014, 141, 224103). The partition functions are calculated by including all bound energy levels of the isotopologues, up to their dissociation limits, plus the quasi-bound levels lying below the centrifugal potential barriers. For the homonuclear isotopologues, H2, D2, and T2, we also determine the partition functions and thermodynamic quantities of the normal mixtures using the statistical treatment recently proposed by Colonna et al. (Colonna, G.; D'Angola, A.; Capitelli, M. Int. J. Hydrogen Energy 2012, 37, 9656) based on the definition of the partition function of the mixture, which avoids inconsistencies in the values of the thermodynamic quantities depending directly on the internal partition function, in the high-temperature limit.
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Affiliation(s)
- José Zúñiga
- Departamento
de Química Física, Universidad
de Murcia, 30100 Murcia, Spain
| | - Adolfo Bastida
- Departamento
de Química Física, Universidad
de Murcia, 30100 Murcia, Spain
| | - Alberto Requena
- Departamento
de Química Física, Universidad
de Murcia, 30100 Murcia, Spain
| | - Javier Cerezo
- Departamento
de Química, Universidad Autónoma
de Madrid, 28049 Madrid, Spain
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Buchowiecki M. Uncertainty of High Temperature Heat Capacities: The Case Study of the NH Radical. J Phys Chem A 2021; 125:795-800. [PMID: 33448217 DOI: 10.1021/acs.jpca.0c09512] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The difficulties in calculation of high temperature heat capacities and discrepancies between available data are discussed in the case of the NH molecule. The source of those inaccuracies are the underlining potential energy curves. The relevant partition functions and heat capacities are calculated with the classical Wigner-Kirkwood corrected method. In addition to the ground electronic state, also four excited states are taken into account. Two potential energy curves and experimental energy levels of the ground state are considered.
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Affiliation(s)
- Marcin Buchowiecki
- Insitute of Physics, University of Szczecin, Wielkopolska 15 St, 70-451 Szczecin, Poland
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Buchowiecki M. Vibrational Partition Function for the Multitemperature Theories of High-Temperature Flows of Gases and Plasmas. J Phys Chem A 2020; 124:4048-4052. [DOI: 10.1021/acs.jpca.0c01161] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marcin Buchowiecki
- Insitute of Physics, University of Szczecin, Wielkopolska 15 St, 70-451 Szczecin, Poland
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Szekeres B, Pártay LB, Mátyus E. Direct Computation of the Quantum Partition Function by Path-Integral Nested Sampling. J Chem Theory Comput 2018; 14:4353-4359. [PMID: 29944376 DOI: 10.1021/acs.jctc.8b00368] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the present work we introduce a computational approach to the absolute rovibrational quantum partition function using the path-integral formalism of quantum mechanics in combination with the nested sampling technique. The numerical applicability of path-integral nested sampling is demonstrated for small molecules of spectroscopic interest. The computational cost of the method is determined by the evaluation time of a point on the potential energy surface (PES). For efficient PES implementations, the path-integral nested sampling method can be a viable alternative to the direct-Boltzmann-summation technique of variationally computed rovibrational energies, especially for medium-sized molecules and at elevated temperatures.
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Affiliation(s)
- Béla Szekeres
- Institute of Chemistry , Eötvös Loránd University , Pázmány Péter sétány 1/A , Budapest H-1117 , Hungary.,Department of Numerical Analysis, Faculty of Informatics , Eötvös Loránd University , Pázmány Péter sétány 1/C , Budapest H-1117 , Hungary
| | - Lívia B Pártay
- Department of Chemistry , University of Reading , Whiteknights, Reading RG6 6AD , United Kingdom
| | - Edit Mátyus
- Institute of Chemistry , Eötvös Loránd University , Pázmány Péter sétány 1/A , Budapest H-1117 , Hungary
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Buchowiecki M. Ro-vibrational coupling in high temperature thermochemistry of the BBr molecule. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2017.12.051] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Partition functions of thermally dissociating diatomic molecules and related momentum problem. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.09.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Buchowiecki M, Prątnicki F. High temperature partition function – a key role of ro-vibrational coupling and inflection points. Mol Phys 2017. [DOI: 10.1080/00268976.2017.1334132] [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]
Affiliation(s)
- Marcin Buchowiecki
- Institute of Physics, Department of Mathematics and Physics, University of Szczecin, Szczecin, Poland
| | - Filip Prątnicki
- Institute of Physics, Department of Mathematics and Physics, University of Szczecin, Szczecin, Poland
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Wendland D, Ballenegger V, Alastuey A. Quantum partition functions of composite particles in a hydrogen-helium plasma via path integral Monte Carlo. J Chem Phys 2014; 141:184109. [PMID: 25399134 DOI: 10.1063/1.4900984] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We compute two- and three-body cluster functions that describe contributions of composite entities, like hydrogen atoms, ions H(-), H2(+), and helium atoms, and also charge-charge and atom-charge interactions, to the equation of state of a hydrogen-helium mixture at low density. A cluster function has the structure of a truncated virial coefficient and behaves, at low temperatures, like a usual partition function for the composite entity. Our path integral Monte Carlo calculations use importance sampling to sample efficiently the cluster partition functions even at low temperatures where bound state contributions dominate. We also employ a new and efficient adaptive discretization scheme that allows one not only to eliminate Coulomb divergencies in discretized path integrals, but also to direct the computational effort where particles are close and thus strongly interacting. The numerical results for the two-body function agree with the analytically known quantum second virial coefficient. The three-body cluster functions are compared at low temperatures with familiar partition functions for composite entities.
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Affiliation(s)
- D Wendland
- Laboratoire de Physique, Ecole Normale Supérieure de Lyon, UMR CNRS 5672, 46 allée d'Italie, 69364 Lyon Cedex 07, France
| | - V Ballenegger
- Institut UTINAM, Université de Franche-Comté, UMR CNRS 6213, 16, route de Gray, 25030 Besançon Cedex, France
| | - A Alastuey
- Laboratoire de Physique, Ecole Normale Supérieure de Lyon, UMR CNRS 5672, 46 allée d'Italie, 69364 Lyon Cedex 07, France
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Aquilanti V, Ragni M, Bitencourt ACP, Maciel GS, Prudente FV. Intramolecular Dynamics of RS−SR′ Systems (R, R′ = H, F, Cl, CH3, C2 H5): Torsional Potentials, Energy Levels, Partition Functions. J Phys Chem A 2009; 113:3804-13. [DOI: 10.1021/jp8094215] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vincenzo Aquilanti
- Dipartimento di Chimica, Università di Perugia, 06123 Perugia, Italy, and Instituto de Física, Universidade Federal da Bahia, 40210-340 Salvador, Bahia, Brazil
| | - Mirco Ragni
- Dipartimento di Chimica, Università di Perugia, 06123 Perugia, Italy, and Instituto de Física, Universidade Federal da Bahia, 40210-340 Salvador, Bahia, Brazil
| | - Ana C. P. Bitencourt
- Dipartimento di Chimica, Università di Perugia, 06123 Perugia, Italy, and Instituto de Física, Universidade Federal da Bahia, 40210-340 Salvador, Bahia, Brazil
| | - Glauciete S. Maciel
- Dipartimento di Chimica, Università di Perugia, 06123 Perugia, Italy, and Instituto de Física, Universidade Federal da Bahia, 40210-340 Salvador, Bahia, Brazil
| | - Frederico V. Prudente
- Dipartimento di Chimica, Università di Perugia, 06123 Perugia, Italy, and Instituto de Física, Universidade Federal da Bahia, 40210-340 Salvador, Bahia, Brazil
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Bitencourt ACP, Ragni M, Maciel GS, Aquilanti V, Prudente FV. Level distributions, partition functions, and rates of chirality changing processes for the torsional mode around O–O bonds. J Chem Phys 2008; 129:154316. [DOI: 10.1063/1.2992554] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Prudente FV, Varandas AJC. A Direct Evaluation of the Partition Function and Thermodynamic Data for Water at High Temperatures. J Phys Chem A 2002. [DOI: 10.1021/jp020797b] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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