Calculation of wave functions in the subbarrier region using 1/n expansion

A method is developed for calculating wave functions in the subbarrier region on the basis 1/n expansion. This method is used to calculate the asymptotic coefficient clp at the origin. To illustrate the accuracy of the method the results are compared with results of numerical calculations for power-law potentials, short-range Yukawa potentials, and exponential potentials. Calculations are performed for node-free states and for states with radial quantum number p = 1. The calculated correction of order 1/n is shown to considerably increase the accuracy of 1/n expansion, especially for p = 1 states (at n ∼ 1, a zero-order approximation for such states is only an estimate). 16 refs., 3 figs., 3 tabs