On the electron affinity of TCNQ

The electron affinity of 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) has been studied with density functional theory and coupled cluster (CC) procedures. The adiabatic electron affinity of TCNQ calculated with the B3LYP method is about 1 eV higher than the available experimental value. At the CCSD(T) level, the theoretical result is overestimated by more than 0.4 eV. The electron affinity computed for TCNQ is larger than that obtained for tetracyanoethylene at all levels of calculation, exactly the opposite of what is observed experimentally. Accordingly, a call for an additional empirical measurement of such a property is made.