A study of K+–He and K+–Kr atomic interaction potentials based on transverse diffusion measurements

Testing ion-neutral interaction potentials using calculated ion transport coefficients

Several commonly measured ion transport coefficients were investigated in order to determine their sensitivity for testing and comparing proposed ion-neutral interaction potentials. A variety of positive ions, negative ions, neutrals, and temperatures were included in order to draw as general a conclusion as possible. All transport coefficients considered were found to be sufficiently sensitive to be used to clearly distinguish between less and more accurate interaction potentials. It was also found that the longitudinal diffusion coefficient is the most sensitive test, followed by both the transverse diffusion coefficient and the ratio of the longitudinal diffusion coefficient to mobility, followed by the ratio of the transverse diffusion coefficient to mobility and that the mobility is the least sensitive test. When presently achievable levels of experimental error were also taken into account, however, there was no significant difference in the sensitivities.

Spectroscopy of K[sup +]⋅Rg and transport coefficients of K[sup +] in Rg (Rg=He–Rn)

Ab initio calculations employing the coupled-cluster method, with single and double substitutions and accounting for triple excitations noniteratively [CCSD(T)], are used to obtain accurate potential energy curves for the K(+)He, K(+)Ne, K(+)Ar, K(+)Kr, K(+)Xe, and K(+)Rn cationic complexes. From these potentials, rovibrational energy levels and spectroscopic parameters are calculated. In addition, mobilities and diffusion coefficients for K(+) cations moving through the six rare gases are calculated, under conditions that match previous experimental determinations. A detailed statistical comparison of the present and previous potentials is made with available experimental data, and critical conclusions are drawn as to the reliability of each set of data. It is concluded that the present ab initio potentials match the accuracy of the best model potentials and the most reliable experimental data.