ESR results on the laser-active Tl°(1) centers in RbCl and KBr

The ESR spectra, the production, and some optical excitation properties of the laser-active Tl°(1) centers in ${\mathrm{Tl}}^{+}$-doped KBr and RbCl are discussed. The $g$ values and hyperfine components are comparable to the KCl data obtained in an earlier paper but the linewidths are much larger (16 mT vs 2.7 mT). One concludes that the amount and the nature of the delocalization of the ${\mathrm{Tl}}^{0}6p$ electron is similar to that in KCl. These results correlate well with the optical absorption and luminescence data, which do not vary drastically for Tl°(1) among all the alkali halides.