Broadening and shift of calcium lines by van der Waals interaction with argon atoms and by electron impact

Line broadening and shift of two neutral and two ionic lines of calcium were investigated by means of a gas-stabilized arc running between a carbon cathode and a calcium anode in a high-pressure argon atmosphere. Line broadening parameters for van der Waals interaction and for electron impact were obtained from the total line profiles by a separation method involving the different dependence of the two effects on temperature and on number densities. The results were compared with theoretical values from Lindnolm's theory and from electron impact calculations by Griem. (auth)