Publication:
Ab initio potential energy surfaces for the O₂-O₂ system and derived thermophysical properties

cris.virtual.departmentThermodynamik
cris.virtual.departmentbrowseThermodynamik
cris.virtual.departmentbrowseThermodynamik
cris.virtualsource.department96d8e6e1-6361-46c5-ae2c-a84605aadf12
dc.contributor.authorHellmann, Robert
dc.date.issued2023-09-14
dc.description.abstractNew intermolecular potential energy surfaces (PESs) for the quintet, triplet, and singlet states of two rigid oxygen (O₂) molecules in their triplet ground electronic states were developed. Quintet interaction energies were obtained for 896 O₂-O₂ configurations by supermolecular coupled cluster (CC) calculations at levels up to CC with single, double, triple, and perturbative quadruple excitations [CCSDT(Q)] with unrestricted Hartree-Fock (UHF) reference wave functions. Corrections for scalar relativistic effects were calculated as well. Triplet interaction energies were obtained by combining the quintet interaction energies with accurate estimates for the differences between the quintet and triplet energies obtained at the UHF-CCSD(T) level of theory. Here, we exploited the fact that the triplet state is almost identical to the readily accessible "broken-symmetry" state, as shown by Valentin-Rodríguez et al. [J. Chem. Phys. 152, 184304 (2020)]. The singlet interaction energies were estimated from the quintet and triplet interaction energies by employing the Heisenberg Hamiltonian description of the spin splittings. The three PESs are represented analytically by site-site models with five sites per molecule and anisotropic site-site interactions. To validate the PESs, we calculated at temperatures from 55 to 2000 K the second virial coefficient using statistical thermodynamics and the shear viscosity, thermal conductivity, and self-diffusion coefficient in the dilute gas phase using the kinetic theory of molecular gases. The calculated property values are in excellent agreement with the most accurate experimental data from the literature. Therefore, we also propose new reference correlations for the investigated properties based solely on the calculated values.
dc.description.versionNA
dc.identifier.doi10.1063/5.0166781
dc.identifier.issn1089-7690
dc.identifier.issn0021-9606
dc.identifier.issn1089-7690
dc.identifier.pmid37682206
dc.identifier.scopus2-s2.0-85170199978
dc.identifier.urihttps://openhsu.ub.hsu-hh.de/handle/10.24405/15172
dc.language.isoen
dc.publisherAIP Publishing
dc.relation.journalThe Journal of Chemical Physics
dc.relation.orgunitThermodynamik
dc.relation.orgunitDTEC.bw
dc.rights.accessRightsmetadata only access
dc.titleAb initio potential energy surfaces for the O₂-O₂ system and derived thermophysical properties
dc.typeResearch article
dcterms.bibliographicCitation.originalpublisherplaceMaryland
dspace.entity.typePublication
hsu.peerReviewed
hsu.uniBibliography
oaire.citation.endPage17
oaire.citation.issue10
oaire.citation.startPage1
oaire.citation.volume159
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