Charge migration in metal-organic frameworks

Charge transport in two zinc metal-organic frameworks (MOFs) has been investigated using periodic semiempirical molecular orbital calculations with the AM1* Hamiltonian. Restricted Hartree-Fock calculations underestimate the band gap (Koopmans theorem), which however becomes more realistic when the wavefunction is allowed to become unrestricted. Charge-transport simulations using propagation of the electron- or hole-density in imaginary time allow charge-transport paths to be determined, although the calculated mobilities must still be improved. In general, the techniques discussed appear to be useful for investigating electroactive MOFs.