A reparametrization approach of the B3LYP functional based on the equilibrium temperature of the spin crossover

The theoretical study of the electronic structure of spin crossover compounds is very challenging due to the technical limitations of highly accurate ab-initio methods and/or the inaccuracies of density functional methods in the prediction of low --spin/high-spin energy splitting. However, calculations using the reparametrized functionals could improve the results. We present an investigation of the HS/LS energy gap of a typical spin crossover compound using several DFT functionals. We propose a reparametrization approach based on the equilibrium temperature of the spin crossover compounds leading to reasonable estimation of the HS/LS energy gap. In fact, the proposed approach is very important to match the used functional to the considered spin crossover compound.