Temperature dependence of spectral lineshifts in pressure broadening
W. C. Kreye, John F. Kielkopf
An exact quantum adiabatic evaluation of the shift of an isolated spectral line is applied to the potassium 7s-4p transition perturbed by argon. The long-range interaction of excited alkali states with noble gases is computed with a large basis set of unperturbed atomic states, a multipole interaction and a pseudopotential to compare with a measurement of the dependence of the shift on temperature. The parameters of the theoretical potassium-argon excited-state potential are determined by adjusting the theoretical temperature dependence to fit the observations. Previous pseudopotential models, fitted to ground-state interactions derived from scattering experiments, show weaker long-range interactions than the authors find. The conclusions are consistent with independent line wing experiments on this and other alkali-noble-gas systems that reveal significant interactions at long range.
Journal of Physics B Atomic Molecular and Optical Physics•Jan 14, 1991•3 citations