  We provide an elementary description of the dynamics of defect centers in
crystals in terms of a quantum optical master equation which includes
spontaneous decay and a simplified vibronic interaction with lattice phonons.
We present the general solution of the dynamical equation by means of the
eigensystem of the Liouville operator and exemplify the usage of this damping
basis to calculate the dynamics of the electronic and vibrational degrees of
freedom and to provide an analysis of the spectra of scattered light. The
dynamics and spectral features are discussed with respect to the applicability
for color centers, especially for negatively charged nitrogen-vacancy centers
in diamond.
