Population of levels inHg199followingTl199decay and intermediate coupling calculations forHg199

The electron capture decay of ${}_{}{}^{199}{}_{}{}^{}\mathrm{Tl}$ to levels in ${}_{}{}^{199}{}_{}{}^{}\mathrm{Hg}$ has been reinvestigated. Twenty new transitions are assigned to the ${}_{}{}^{199}{}_{}{}^{}\mathrm{Tl}$ decay scheme and the population of two new levels in ${}_{}{}^{199}{}_{}{}^{}\mathrm{Hg}$ at 750.4 and 1221.2 keV is confirmed. A quasiparticle-phonon coupling model is applied to low-lying levels in ${}_{}{}^{199}{}_{}{}^{}\mathrm{Hg}$. Good agreement with experiment is obtained for the eigenvalues, spectroscopic factors, and electromagnetic transition rates and moments by variation of the $f_{\frac{5}{2}}$ neutron energy and by introducing a phenomenological reduction factor in the coupling matrix element.