Gaussian matrix elements of the operator X: Reduction to confluent hypergeometric functions

✍ Scribed by A. W. Niukkanen

• Publisher: John Wiley and Sons
• Year: 1980
• Tongue: English
• Weight: 634 KB
• Volume: 18
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/qua.560180305

✦ Synopsis

Abstract

A new method has been proposed for calculating the Gaussian matrix elements of the interaction operator represented by an arbitrary degree of interelectron distance X. The method is based on the expansion of two‐electron integrals as the sum of one‐electron integrals which in turn admit compact operator representation in terms of confluent hypergeometric functions. The generating differential operator has been shown to be related to the modified Hermitian polynomials. The standard structure of the special functions encountered in this approach is useful in studying the analytical behavior of the integrals and makes it possible to obtain for these integrals recurrence relations, direct algebraic expressions in the forms of finite sum of confluent hypergeometric functions, integral representations, and asymptotic properties. Unlike the usual methods based on integral transformation of the interaction operator, the proposed approach has a wider field of application, and in addition, leads to compact and convenient analytical expressions. The idea of using differential properties of integrals to simplify the integrand structure gives the proposed approach a certain resemblance to that suggested by Boys but not developed in detail in his pioneer work.