Collision broadening and shift in the λ6573 line of calcium

Abstract

The effects of foreign gas pressures of up to 1 atm on the intensity distribution in a spectral line have been measured to an accuracy of the order of 0·001 cm^-1 with the use of a high resolution grating spectrograph. Results are presented for the broadening and shift of the λ6573 line of calcium when perturbed by addition of He, Ne, Ar and Kr. These results show the linear variation of both broadening and shift with perturbing particle density as predicted by the Lindholm impact theory but a quantitative interpretation demands the use of an interaction potential between radiating and perturbing atoms containing both attractive and repulsive components.