JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM, cilt.809, ss.103-113, 2007 (SCI İndekslerine Giren Dergi)
A new approximation formalism is applied to study the bound states of the Hellmann potential, which represents the superposition of the attractive Coulomb potential -a/r and the Yukawa potential bexp(-delta r)/r of arbitrary strength h and screening parameter delta. Although the analytic expressions for the energy eigenvalues E(n,l) yield quite accurate results for a wide range of n, f in the limit of very weak screening, the results become gradually worse as the strength b and the screening coefficient 6 increase. This is because that the expansion parameter is not sufficiently small enough to guarantee the convergence of the expansion series for the energy levels. (C) 2007 Elsevier B.V. All rights reserved.