GENERALIZED DOUBLE EXPONENTIAL POTENTIAL FUNCTIONS FOR DIATOMIC-MOLECULES

Two variants nf the double exponential potential function and their vi rial modifications are proposed and tested. The first in reduced varia bles is F(t) = e(-mt){[m(m(2) - 1)(-1/2) - 1]exp[-(m(2) - 1)(1/2)t] - [m(m(2) - 1)(-1/2) + 1]exp/(m(2) - 1)(1/2)t]} where r = kappa s = kapp a(R - R-e))/R-e, kappa is a scaling constant, and m is a parameter. Th e second is G(t) = e(-mt){e(-mt) - exp[(m(2) - 1)(1/2)t] + exp[-(m(2) - 1)(1/2)]}. For or < 1, F(t) and G(t) are expressible in terms of tri gonometric functions. A new procedure multiplication by e(s)/(1 + s)] is illustrated that modifies potential functions so that they necessar ily satisfy the molecular virial theorem. The generalized double expon ential functions generate scaled first and second Dunham coefficients that well describe the experimental results for both ground and excite d states. (C) 1997 John Wiley & Sons, Inc.