Quantum Monte Carlo study of porphyrin transition metal complexes

Diffusion quantum Monte Carlo (DMC) calculations for transition metal ( M ) porphyrin complexes ( M Po , M = Ni , Cu , Zn ) are reported. We calculate the binding energies of the transition metal atoms to the porphin molecule. Our DMC results are in reasonable agreement with those obtained from density functional theory calculations using the B3LYP hybrid exchange-correlation functional. Our study shows that such calculations are feasible with the DMC method.