Optical spectra of systems with nearly unstable excited states: modulated lambda-shaped spectra

Theory of optical spectra of impurity centres in crystals: general consideration of quadratic vibronic coupling

“…In [13], one of the authors proposed a new approach which is based on algebraic relations between the Fourier transform of the spectrum and the Fourier-amplitudes of one-and two-phonon transitions. Recently, by applying this method, a solution of the problem of the transition between electronic states with hard and soft phonon dynamics was proposed [14][15][16] (in this case the quadratic coupling is strong).…”