Molecular orientation in conductive Langmuir-Blodgett films of a charge-transfer complex

The molecular orientation in Langmuir-Blodgett films of a 3:2 charge-transfer complex of tetramethyltetrathiafulvalene and tetradecyltetracyanoquinodimethane [(TMTTF)3(C14TCNQ)2] is discussed from the observed anisotropic ESR spectra at the K and X bands. Anisotropy of g values shows the existence of in-plane preferential orientation of the complex with the p-pi-orbital axis and long axis of the TMTTF molecules parallel and perpendicular to the dipping direction of the substrate, respectively. The effect of aging on ESR spectra of the system is also reported. The decrease in the difference in linewidth at the K and X bands observed for the external magnetic field normal to the film plane indicates the reduction in the degree of misorientation of the molecules by aging.