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Computational study of vertical ionization potentials using density functional theory and Green’s function methods

TitleComputational study of vertical ionization potentials using density functional theory and Green’s function methods
Publication TypeJournal Article
Year of Publication2000
AuthorsHu, CH, Chong, DP
JournalJournal of the Chinese Chemical Society
Volume47
Pagination141-147
Date PublishedFeb
Type of ArticleArticle
ISBN Number0009-4536
KeywordsALGORITHM, APPROXIMATION, density functional theory, ENERGIES, Green’s function, MOLECULES, PHOTOELECTRON-SPECTRA, POTENTIALS, SPECTROSCOPY, vertical ionization
Abstract

Over one hundred vertical ionization potentials (VIPs) were computed using density functional theory (DFT) and Green’s function (GF) based methods. The DFT approaches include the unrestricted transition state (uTS) and unrestricted diffuse ionization (uDI) approximations using the Becke88-Perdew86 exchange-correlation functional. Green’s function methods include the outer-valence GF (OVGF) approach, the parametrized GF2 (pGF2), and the parametrized GF2 times screened interaction (pGW2) approximations. DFT computations of IPs using the uTS approximation was found to be nearly as accurate as those predicted using the elaborate OVGF method. The much more computationally efficient uDI approximation provides predictions of moderate accuracy and is recommended for computing IPs for larger molecules. We have observed that the average absolute deviations from a uDI calculation using poorer basis set (DZVP) and poorer geometry (AM1 optimization) is only slightly larger.

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