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Theoretical study of valance photoelectron spectra of hypoxanthine, xanthine, and caffeine using direct symmetry‐adapted cluster/configuration interaction methodology
Author(s) -
Farrokhpour Hossein,
Fathi Fariman
Publication year - 2011
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.21832
Subject(s) - chemistry , natural bond orbital , ionization energy , spectral line , atomic physics , ionization , cluster (spacecraft) , symmetry (geometry) , configuration interaction , basis set , atomic orbital , excited state , molecular physics , computational chemistry , ion , physics , density functional theory , electron , geometry , mathematics , organic chemistry , astronomy , computer science , programming language , quantum mechanics
Abstract UV photoelectron spectra of hypoxanthine, xanthine, and caffeine, up to 20 eV, were calculated and compared with the experimental spectra reported in literature. The calculations were performed using a novel version of the quantum mechanical symmetry‐adapted cluster/configuration interaction (SAC‐CI) method termed, direct SAC‐CI. The Duning/Huzinaga valance double‐zeta D95+(d,p) Gaussian basis set was also employed with this method. The ionization energies and intensities were calculated, and the corresponding spectral bands were assigned. Natural bonding orbital (NBO) calculations were employed for better spectral band assignment. The calculated ionization energies and intensities reasonably produced the experimental photoelectron spectra. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011