Thermal broadening and shift of the energy levels of TR3+ Ions in Crystals

A theoretical consideration is made of the thermal broadening and shift of the impurity energy levels in crystals doped with TR3+ ions using the Hamiltonian of electron-phonon interaction containing linear terms in the lattice variables. In the method developed for the calculation of these effects the real phonon density distribution is used for the host crystal. The information about this distribution is obtained from the spectrum of vibrational satellites of zero-phonon lines. The calculations are carried out for the thermal broadening and the shift of some lines in the 3/2 → 4I11/2 luminescence band of the Nd3+ ion in an YAIO3 host crystal.