Absorption Band Spectra of Silver Bromide and Silver Iodide Vapors

Abstract

Vibrational quantum analysis.—The absorption spectra of the vapors of AgBr and AgI have been photographed with a 21 foot concave grating. Band heads were measured in the region 3165-3501A for AgBr and 3016-3556A for AgI. Continuous absorption below 3350A, with its maximum at about 3170A, was observed for both molecules. A vibrational analysis similar to that already carried out for AgCl gives the following equations for $\{\nu ={\nu }_e+{{\omega }_e}^{\prime }{u}^{\prime }-{{\omega }_e}^{\prime }{x_e}^{\prime }{u}^{\prime 2}+{{\omega }_e}^{\prime }{y_e}^{\prime }{u}^{\prime 3}-{{\omega }_e}^{\prime \prime }{u}^{\prime \prime }+{{\omega }_e}^{\prime \prime }{x_e}^{\prime \prime }{u}^{\prime \prime 2}\}\{\mathrm{AgBr}: \nu =,31280.43+180.8u^{\prime }-4.45\mathrm{}{u}^{\prime 2}-0.060\mathrm{}{u}^{\prime 3}-247.72\mathrm{}{u}^{\prime \prime }+0.6795\mathrm{}{u}^{\prime \prime 2}\}\{\mathrm{AgI}: \nu =,31190.87+131.3u^{\prime }-5.175\mathrm{}{u}^{\prime 2}-0.050\mathrm{}{u}^{\prime 3}-206.18\mathrm{}{u}^{\prime \prime }+0.4327\mathrm{}{u}^{\prime \prime 2}\}$ where $u=v+\frac{1}{2}$. Rotational structure is not sufficiently resolved for analysis. The band heads are single. The electron jump is not identified, but the most likely possibility is ${}_{}{}^1{}_{}{}^{}\Sigma -{}_{}{}^1{}_{}{}^{}\Sigma$.