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Photoelectron spectra, penning ionization electron spectra, and character of canonical molecular orbitals
Author(s) -
Chen ErhHao,
Chang TseChiang
Publication year - 1998
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/(sici)1096-987x(199806)19:8<882::aid-jcc7>3.0.co;2-l
Subject(s) - natural bond orbital , chemistry , molecular orbital , penning ionization , molecular orbital theory , molecular orbital diagram , localized molecular orbitals , orbital hybridisation , non bonding orbital , lone pair , valence bond theory , basis set , atomic orbital , computational chemistry , atomic physics , ionization , molecule , physics , electron , density functional theory , quantum mechanics , ion , organic chemistry
When canonical molecular orbitals are expanded in terms of a set of localized molecular orbital building blocks, called bond orbitals, the character of the canonical molecular orbitals can be characterized according to the component bond orbitals resembling the core, lone pair, and localized bond building blocks in an intuitive Lewis structure. Weinhold's natural bond orbital method can produce a unique Lewis structure with total occupancy of its occupied bond orbitals exceeding 99.9% of the total electron density for simple molecules. Two useful indices, Lewis bond order and weight of lone pair orbitals, can be defined according to the weights of the bonding and lone pair components of this unique Lewis structure. Calculation results for molecules N 2 , CO, CS, NO, HCN, C 2 H 2 , H 2 O, and H 2 S show that the former index can account for the vibrational structures of photoelectron spectroscopy, whereas the latter index can account for the band intensity enhancement of Penning ionization electron spectroscopy. © 1998 John Wiley & Sons, Inc. J Comput Chem 19: 882–892, 1998