ON THE CONVERGENCE RATE OF A CUSP-CORRECTED DAMPED MULTIPOLE EXPANSION FOR THE 2ND-ORDER H-H+ INDUCTION ENERGY

The improvement in the convergence rate of the damped multipole expans ion for the second order H-H+ induction energy due to the inclusion in to the first-order function of a term satisfying the electron-proton c usp condition is quantitatively investigated. Following a technique su ggested by Schwartz, the multipole contributions to the energy are put in the form of series ordered by inverse powers of the quantum number l. It is shown that, for high values of l, the dependence of the lead ing terms is raised from l(-4) to l(-6) by the cusp correction.