Collision broadening and shift in the 6s-7p doublet of caesium

Abstract

The broadening and shift of the caesium 4593 AA and 4555 AA lines have been measured when the lines are formed in absorption at 400K under pressures of Ne, Ar and Xe up to 150 Torr. Neon-broadened profiles were symmetrical over the entire pressure range whereas argon- and xenon-broadened profiles became asymmetric as the pressure increased. These observations are shown to be compatible with a collision theory which includes radiation during collisions. Compared to the 4555 AA line, the 4593 AA line shows slightly greater broadening and a significantly smaller shift. Combination of the present results with data obtained by other workers for the 4593 AA line at 4500K reveals a different temperature dependence for argon- as compared to neon-broadening.