Alternative square-integrable (L2) basis functions, the oscillating Hermite Gaussian functions (OHGF's), are proposed for describing the continuum orbitals in L2 calculations on molecules. Each function is the product of a Hermite Gaussian function (HGF), which gives the proper dumping and angular factor, and a radial trigonometric function, cos(kr), which describes the oscillating asymptotic behavior of a continuum orbital. Analytic expressions for the one- and two-electron integrals involving s-type OHGF's and many-center s-type HGF's are derived and their numerical implementation is discussed in detail. The present proposal of adopting a mixed basis set of OHGF's and many-center HGF's for the L2 description of bound and continuum molecular states is compared with the other types of basis functions currently employed. With respect to these, it requires a greater computational effort in the integral evaluation, but it also allows an accurate description of the electronic continuum in general polyatomic systems.
ALTERNATIVE BASIS FUNCTIONS FOR L2 CALCULATIONS ON THE MOLECULAR CONTINUUM .1. THE BASIC PROTOTYPE INTEGRALS
FORTUNELLI A;CARRAVETTA;
1992
Abstract
Alternative square-integrable (L2) basis functions, the oscillating Hermite Gaussian functions (OHGF's), are proposed for describing the continuum orbitals in L2 calculations on molecules. Each function is the product of a Hermite Gaussian function (HGF), which gives the proper dumping and angular factor, and a radial trigonometric function, cos(kr), which describes the oscillating asymptotic behavior of a continuum orbital. Analytic expressions for the one- and two-electron integrals involving s-type OHGF's and many-center s-type HGF's are derived and their numerical implementation is discussed in detail. The present proposal of adopting a mixed basis set of OHGF's and many-center HGF's for the L2 description of bound and continuum molecular states is compared with the other types of basis functions currently employed. With respect to these, it requires a greater computational effort in the integral evaluation, but it also allows an accurate description of the electronic continuum in general polyatomic systems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.