The Possibility of FVMO Method by Means of Only 1s-Type Gaussian Functions


Faculty of Business Management, Takachiho University
19-1, Ohmiya 2 chome, Suginami-ku, Tokyo 168-8508, Japan

(Received: August 11, 2009; Accepted for publication: October 2, 2009)

Dedicated to the late Prof. Kazuhide MORI.

Unpublished trial calculations for 2p state (2P) and 3d state (2D) using the fully variational molecular orbital (FVMO) method with only 1s-type Gaussian type functions (GTFs) as the basis set are reported. All calculations in this study have been performed by the FVMO program GAMERA augmented by ROHF part and C2v symmetry consideration. Antisymmetric pairs of 1s-type GTFs have been optimized for the orbital exponents and the position of the orbital center simultaneously and it is found that the optimized exponents are approximately the same as but slightly larger than those in standard 2p-type GTF expansions in all cases (Table 3). Total energies (orbital energies) with both types of GTF expansions are nearly the same but those with antisymmetric pairs of 1s-type GTFs are slightly higher (Table 2). The trial for 3d orbital with the expansion of quadruple 1s-type GTFs was not successful. However, the present study implies that the FVMO method with only 1s-type GTFs as the basis set will be promising if the possibility, the advantage, and the implementation of the program are investigated.

Keywords: FVMO, Simultaneous optimization of orbital exponents and the positions of orbital centers, Gaussian type function(GTF), Hydrogen atom, 1s-type GTF

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