R. Moszynski et al., SYMMETRY-ADAPTED PERTURBATION-THEORY POTENTIAL FOR THE HEK-COEFFICIENTS OF POTASSIUM-IONS IN HELIUM( MOLECULAR ION AND TRANSPORT), The Journal of chemical physics, 101(6), 1994, pp. 4697-4707
The interaction potential for the HeK+ system has been computed as the
sum of attractive and repulsive contributions due to the electrostati
c, exchange, induction, and dispersion interactions using the symmetry
-adapted perturbation theory and a high-level treatment of electron co
rrelation. The zero of the theoretical potential occurs at 4.704 bohr
and the minimum occurs at 5.418 bohr where the potential value is -0.7
79 mhartree. The potential supports 36 bound rovibrational levels, and
the ground state of the HeK+ molecular ion is bound by 125.1 cm(-1).
For all interatomic distances the ab initio potential agrees very well
with the empirical potential obtained by direct inversion of the K+ m
obilities in gaseous helium and disagrees with the potential obtained
from the ion-beam scattering cross section data. The ab initio potenti
al has been used to compute the transport coefficients of potassium io
ns in helium gas over a wide range of temperature and reduced field st
rength. A very good agreement of the calculated transport coefficients
with the preponderance of the existing experimental data is observed.
This agreement leads us to believe that the present interaction poten
tial is accurate to within a few percent at all separations between 4.
0 and 10.0 bohr and, consequently, represents the most accurate potent
ial available for the HeK+ system.