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Method/basis set dependence of the traceless quadrupole moment calculation for N 2 , CO 2 , SO 2 , HCl, CO, NH 3 , PH 3 , HF, and H 2 O
Author(s) -
Höfinger Siegfried,
Wendland Martin
Publication year - 2001
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.1625
Subject(s) - quadrupole , basis set , chemistry , dipole , moment (physics) , ab initio , basis (linear algebra) , computational chemistry , molecule , yield (engineering) , ab initio quantum chemistry methods , set (abstract data type) , molecular physics , atomic physics , density functional theory , thermodynamics , physics , quantum mechanics , mathematics , geometry , organic chemistry , computer science , programming language
Dipole moments and traceless quadrupole moments for a training set of nine molecules—N 2 , CO 2 , SO 2 , HCl, CO, NH 3 , PH 3 , HF, and H 2 O—were deduced from the final optimized density matrices of a series of ab initio calculations, thereby employing different levels of theory with varying basis set quality. All the results were obtained in a true ab initio sense, meaning that at a certain combination of method/basis set, the configurations of the molecules were first subjected to a geometry optimization and only afterwards the dipole and traceless quadrupole moments were derived for the final relaxed structures. All results could be compared to experimental data, thus the quality of the different models with respect to applicability and reliability of calculating molecular moments without any knowledge of structural details of the equilibrium geometries could be evaluated. Generally, a combination of methods that take into account correlation effects, together with a high‐level basis set, was found to yield molecular moments close to the experimental values. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001