Dynamic Jahn-Teller Effect in the ODMR Spectrum of the Self-Trapped Exciton in AgCl Crystals

An isotropic ODMR line other than the ODMR spectra of the self-trapped exciton (STE) with the tetragonal symmetry in AgCl at 4.2 K was observed using X-band and K-band spectrometers. The g value satisfied the relation of g =( g // +2 g ⊥ )/3 where g // and g ⊥ are the g values of the parallel and perpendicular spectra of the STE. The isotropic line is ascribed to motional narrowing of the tetragonal spectra of the STE. This observation of thermal dynamic Jahn-Teller effect of the STE at 4.2 K indicates that the bound electron in the STE lowers the barrier height between three configurations of the static Jahn-Teller distortion of the self-trapped hole (STH).