Az Egri Ho Si Minh Tanárképző Főiskola Tud. Közleményei. 1987. (Acta Academiae Paedagogicae Agriensis : Nova series ; Tom. 18/13)

Tamás Franczia: An analytical method for calculating multicentre integrals built up from GTF-S I

- 28 Introduction

: Let us consider a pair of two valence electrons a quantum mechanical system, which is the chemical bonding pair of a diatomic molecule. Let other valence electrons not be in the above-mentioned chemical bond. It is possible to construct the Hamilton operator of this electron pair if we choose the following work-hypotheses of the suitable ones. If the other electrons of the molecule are not valence electrons but so called core electrons belonging to either one or the other nucleus their effect on either of the valence electrons can be taken into account together with the influence of that nucleus they belong to. The effective potential of a system consisting of a nucleus and its core electrons can be expressed approximately with the aid of many pseudopotentials. i±j These pseudopotentials can be derived from the statistical theory of atoms or from the wave mechanics. ci3,C23,C33 In the case of a valence electron mentioned above the effect of a nucleus and its core electrons on the valence electron can be given - among others - with the following pseudopotential form: VCrO=V CiO+V Cr), lr s r * Z cx_, a V. Cr) -£. - Ű 2 l r r 2(r

2

+d

2] 2[r

2+d

2] rCD = 2 A

tr

p exp (-«^r«).