Acta Phys. -Chim. Sin. ›› 1992, Vol. 8 ›› Issue (03): 307-312.doi: 10.3866/PKU.WHXB19920306

• ARTICLE • Previous Articles     Next Articles

Improvement of Approximate Calculations Based on Semiorthogonalized Orbitals

Ding Fu-Jiang; Zhang Liang-Fu; Li Guang-Nian   

  1. Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610015
  • Received:1990-12-10 Revised:1991-04-18 Published:1992-06-15
  • Contact: Ding Fu-Jiang

Abstract: Kashiwagi used semiorthogonalized orbitals as basis set in quantum chemicalcal culations and proposed a scheme in which two-electron integrals containing orthogonalized orbital pairs were neglected, but the same kind of one-electron integrals were reserved. We proposed in this paper that one-electron integrals containing ortho-gonalized orbital pairs should be neglected too. This improvement makes the calcu-lations more accurate, because nuclear attractive energy is approximately equal to electron repulsive energy in a system. We use simpler orbitals to evaluate threeand four-center integrals, while keeping charge conservation. These two improvements can save a lot of computer time in approximate ab initio calculations.

Key words: Approximate calculation, Semiorthogonalized orbital, Integral approximation, Charge conservation