PMO POTENTIAL AND DIPOLE MOMENT FUNCTIONS OF HYDROGEN-FLUORIDE WITH CORRECT ASYMPTOTIC BEHAVIOR.

Abstract

The PMO potential thus obtained has been improved even more by a special method in which some of its parameters are varied in very small step size until the differences G(, v)('cal)-G(, v)('ex) and B(, v)('cal)-B(, v)('ex) become as small as possible.

A perturbed Morse oscillator potential function for the X('1)(SIGMA)('+) state of HF is improved for large internuclear separation (r) by adding a function of several parameters from which "synthetic" higher-order PMO parameters can be evaluated. These parameters can then be varied until the asymptotic condition (V(r)(--->)D(, e) as r(--->)(INFIN) where D(, e) is the dissociation energy) is achieved.

The vibrational wave functions for this PMO potential were computed by numerical methods. These wave functions were then used in the determination of the dipole moment of X('1)(SIGMA)('+) state of HF as a function of r by fitting it to the experimentally deduced vibrational matrix elements.

Values of the PMO parameters (including the non-adiabatic correction parameter (DELTA) and higher-order PMO parameters) have then been obtained by fitting experimental values of G(, v), B(, v), and D(, v) directly in terms of model parameters. The quality of the PMO potential function found is determined by the agreement between the eigenenergies it predicts (in this work, through solving the radial Schrodinger equation) and the spectroscopically observed ones.

The dipole moment of the X('1)(SIGMA)('+) state of HF were calculated as cubic polynomials in u = r-r(, e), y = 1-e('-a(r-r(, e))), and z = e('a('a(r-r)e('))) - 1. In addition, we found a suitable functional form by which we have been able to obtain the dipole moment of HF with correct asymptotic behavior at both large and small r.