BEDT-TTF salts: microscopic parameters from ab-initio calculations

Extensive ab initio calculations are performed on BEDT-TTF dimeric units singled out from the κ-(BEDT-TTF) 2Cu[N(CN)2]Br (ETBR) structure. From a careful analysis of the results obtained for dimers with total charge ranging from 0 to 4 we are able to get reliable estimates of the Hubbard model parameters.