Pressure Effects of Argon and Helium on the Resonance Lines of Silver

The shift and the broadening of Ag λλ3280 and 3382 produced by argon and helium for pressures up to 83.3 atmospheres at about 950^∘{}C were determined. The shift of Pb 2833 was also measured under the same conditions. Argon produces a red shift and a slight red asymmetry, while helium produces a violet shift and a very slight violet asymmetry for all these lines. The ²P1/2 component of silver resonance lines is shifted more than the ²P3/2 component. The relative difference in the shift is much more pronounced for helium than for argon. For helium the ²P1/2 component is shifted about six times greater than the ²P3/2 component.Both the shift and the broadening appear to be linear with the relative density for argon or helium. The ²P1/2 component produces a shift of 0.289 cm^-1 (red) per unit relative density of argon, and of 0.131 cm^-1 (violet) per unit relative density of helium. The corresponding figures for the ²P3/2 component are 0.248 cm^-1 (red) and 0.023 cm^-1 (violet) per unit r.d. Shifts for Pb 2833 are respectively 0.388 cm^-1 (red) and 0.188 cm^-1 (violet) per unit r.d. for argon and helium.There is no significant difference between the half-widths of the doublet components of the silver lines for helium. They are broadened 0.466 cm^-1 per unit r.d. For argon the ²P3/2 component is broadened slightly more than the ²P1/2 component. The ²P1/2 and the ²P3/2 components are broadened respectively 0.468 cm^-1 and 0.560 cm^-1 per unit r.d. The optical collision diameters as calculated from the half-widths turn out to be 6.50A for He-Ag and 11.3A for A-Ag.