G. Brocks, THEORETICAL-STUDY OF THE CHARGE-TRANSFER IN THE ORGANIC-CRYSTAL OF DIMETHYLQUATERTHIOPHENE AND TETRAFLUORO-TETRACYANOQUINODIMETHANE, Physical review. B, Condensed matter, 55(11), 1997, pp. 6816-6819
The electronic and geometrical structures of the organic charge-transf
er crystal of dimethylquaterthiophene (DMQtT) and tetrafluorotetracyan
oquinodimethane (TCNQF(4)) are calculated self-consistently from first
principles using Car-Parrinello techniques. The calculated electronic
charge transfer from the DMQtT molecule to the TCNQF(4) molecule is 0
.46e +/- 0.05e. This charge transfer is accompanied by a structural ch
ange in which the DMQtT molecule adopts a more quinoid geometry (compa
red to the aromatic structure of the neutral DMQtT molecule) and the T
CNQF(4) molecule becomes more aromatic. The electronic structure aroun
d the Fermi level is characterized by one-dimensional charge transfer
states.