Jahn-Teller effect in ZnS:${\mathrm{Fe}}^{2+}$ revisited with a modified Lanczos-type algorithm

We study the Jahn-Teller effect in ZnS:${\mathrm{Fe}}^{2+}$ by means of a modified Lanczos-type algorithm, able to give any excited state of very large quantum systems with good accuracy. The calculations are performed in the energy range of 2945–3580 ${\mathrm{cm}}^{\mathrm{-}1}$, in the framework of a multimode vibronic model. The zero-phonon emission lines (hot lines) are also evaluated. The results are compared with the experimental ones. © 1996 The American Physical Society.