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Collision broadening and shifts in the spectra of neutral and singly ionised calcium

1978; IOP Publishing; Volume: 11; Issue: 10 Linguagem: Inglês

10.1088/0022-3700/11/10/008

1747-3721

N J Bowman, E L Lewis,

Atomic and Molecular Physics

Measurements are reported of the broadening and shifts, due to collision with helium and argon, of the neutral calcium line 4227 AA and the Ca+ resonance lines 3968 and 3933 AA (the solar H and K lines) and the associated lines 8542 and 8662 AA. The lines are obtained in emission from a flow lamp and the profiles recorded from a scanning Fabry-Perot interferometer are analysed numerically. The very nearly equal broadenings of the H and K lines and the corresponding infrared lines indicate that the broadening in both multiplets is essentially determined by the common upper configuration. The observed broadening is between 1.3 and 2 times the predictions of van der Waals theory. Comparison with high-temperature shock-tube measurements indicate that the broadening varies as T0.4+or-0.02 for helium and T0.25+or-0.07 for argon.