Photoelectron Spectrum and Electronic Structure of Tetrathiofulvalene (TTF)

The electronic structure of tetrathiofulvalene (TTF) has been determined from its photoelectron spectrum and the photoelectron data for the tetrahydro derivative of TTF and 1,3-dithiolane. Correlations of the ionization potentials (i.p.) and several molecular orbital calculations are used in the assignment of the photoelectron spectra of these three compounds. The first five i.p. of TTF and their assignment are as follows: 6.92 (3b 1u ), 8.67 (2b 2g ), 9.73 (2b 1u ), 10.16 (a u ) and 10.49 eV (b 3g ). The sixth i.p. at 11.00 eV is tentatively assigned to the 1b 2g level. The electronic structure of TTF is important in understanding the crystal packing and band structure of the highly conducting salt, TTF•TCNQ.