Effects of Intra- and Intercenter Interactions in Spin Crossover: Application of the Density Matrix Method to the Nonequilibrium Low-Spin↔High-Spin Transitions Induced by Light

A microscopic model of nonequilibrium light-induced phase transitions in spin crossover systems based on the solution of the equations for the density operator is developed. The conditions of light-induced and thermally induced bistability are revealed. The results are compared with those obtained in the framework of the Glauber's approach. The qualitative explanation of experimental data on a series of spin crossover systems is given.