Spectroscopic analysis of a collisional complex. Redistribution calculation for the K(5P-4S) doublet perturbed by neon

Abstract

The close-coupled theory of collisions in a radiative field is applied to the calculation of the absorption profile for the K(5P-4S) doublet broadened by collisions with Ne. Using both quantal and semiclassical approaches allows quantitative results to be obtained and also points out the more important physical aspects. The theory gives simultaneously the absorption coefficient, the fine-structure branching ratio and the polarisation redistribution from the line centre, where the impact limit is valid, to the far spectral wings. The analysis of the influence of non-adiabatic couplings shows that the total absorption coefficient is rather insensitive to these couplings but that they play an important role in the fine-structure branching ratio and in the polarisation redistribution. The authors also find a strong dependence of the polarisation redistribution with the curvature of the trajectories.