EVALUATION OF MOLECULAR INTEGRALS IN A MIXED GAUSSIAN AND PLANE-WAVE BASIS BY RYS QUADRATURE

We report on the use of Rys numerical quadrature for the calculation o f two-electron exchange integrals containing two Gaussians and two pla ne-wave functions, and two-electron integrals containing three Gaussia ns and one plane-wave function. Generally, the Rys polynomials for thi s mixed basis set are complex. We present formulas for obtaining their roots and weights that are also generally complex. Rys numerical quad rature provides an alternative method for calculation of integrals of this type that are encountered in the electron-molecule scattering the ory. (C) 1998 Academic Press.