CONVERGENCE ACCELERATION FOR THE KOHN VARIATIONAL METHOD IN THE PRESENCE OF A LONG-RANGE INTERACTION

This paper presents a distorted-wave generalization of the S-matrix ve rsion of the Kohn variational principle developed by Zhang, Chu, and M iller [J. Chem. Phys. 88, 10 (1988)]. For scattering in the presence o f a long-range interaction, the large-r asymptotic solution to the Sch rodinger equation is built into the Kohn variational principle order b y order in an effort to accelerate the convergence of the short-range square integrable part of the basis-set expansion. The improvement in the rate of convergence is demonstrated by applying the method to a lo ng-range model potential. Multichannel scattering is discussed.