Atomic basis sets optimization using the generalized simulated annealing approach: New basis sets for the first row elements

摘要

Atomic basis sets equivalent to the standard STO-3G and STO-6G ones were optimized for the elements of the first row using the generalized simulated annealing (GSA) approach. The atomic energies obtained with the new basis sets are substantially better than the ones obtained with the standard ones. The new basis sets were tested for several diatomic and triatomic molecules, at different levels of calculation. For the molecules at their geometries of equilibrium, the energies obtained with the GSA optimized basis are in general much better than the respective ones obtained with the standard basis. However, for molecules containing hydrogen atoms, the best results, either at the HF or CI level of calculation, are obtained with a combination of the new and the standard bases, which depend on the nature of the other atoms of the molecule. The analysis of the potential energy surfaces for the LiH, BH, and FH molecules showed that the new basis provide a better description of these molecules in all regions of the respective surfaces, although the equilibrium bond distances. The results are quite encouraging and clearly indicate that basis set of DZ and TZ quality better than the standard ones can probably be generated by the GSA approach. (C) 2008 Wiley Periodicals, Inc.