Efficient algorithm for two-center Coulomb and exchange integrals of electronic prolate spheroidal orbitals

JOURNAL OF COMPUTATIONAL PHYSICS

卷:231

Article

Mendl, Christian B.

关键词: Schrodinger equation;    Coulomb integrals;    Prolate spheroidal coordinates;    Diatomic molecules;    Molecular orbitals;    Laguerre expansions;   

DOI  :  10.1016/j.jcp.2012.04.022

来源: Elsevier

【 摘 要 】

We present a fast algorithm to calculate Coulomb/exchange integrals of prolate spheroidal electronic orbitals, which are the exact solutions of the single-electron, two-center Schrodinger equation for diatomic molecules. Our approach employs Neumann's expansion of the Coulomb repulsion 1/vertical bar x-y vertical bar, solves the resulting integrals symbolically in closed form and subsequently performs a numeric Taylor expansion for efficiency. Thanks to the general form of the integrals, the obtained coefficients are independent of the particular wave-functions and can thus be reused later. Key features of our algorithm include complete avoidance of numeric integration, drafting of the individual steps as fast matrix operations and high accuracy due to the exponential convergence of the expansions. Application to the diatomic molecules O-2 and CO exemplifies the developed methods, which can be relevant for a quantitative understanding of chemical bonds in general. (C) 2012 Elsevier Inc. All rights reserved.

【 授权许可】

Free