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Generalized molecular orbital theory: Ground state and ionization potentials of water and dinitrogen
Author(s) -
Hall Michael B.
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560160822
Subject(s) - atomic orbital , molecular orbital , molecular orbital theory , slater type orbital , chemistry , basis set , ionization , atomic physics , ionization energy , configuration interaction , ground state , complete active space , computational chemistry , physics , molecule , density functional theory , quantum mechanics , ion , electron , organic chemistry , excited state
Generalized molecular orbital (GMO) theory is a limited multiconfiguration self‐consistent field (MCSCF) procedure, which provides a simple means of obtaining a set of optimized primary orbitals for use in configuration interaction (CI) calculations. Results for the ground states of H 2 O and N 2 show that the most important GMO orbitals are nearly identical to the natural orbitals from large CI calculations. For H 2 O, our GMO‐CI correlation energy is only 4 mhartrees less than that obtained from an identical CI with the most important natural orbitals. The GMO theory for doublet states provides a facile means of obtaining accurate ionization potentials (IPS) from small CI calculations (30–60 configurations). For the first three IPS of H 2 O the error is less than 0.5 eV while for the first two IPS of N 2 the error is less than 0.1 eV.