Optical transfer integral

The BEDT-TTF trihalides and the related salts attract much attention because of a relatively high superconducting transition temperature. Figure 8 shows the polarized reflectance of a- and (3-(BEDT-TTF)2I3 crystals for two light polarizations. For both phases the electronic reflection bands with a Drude-like edge are observed in two perpendicular polarizations [47]. Drude parameters and transfer integrals of typical (BEDT-TTF)2X salts are 5000 cm-1 < top < 9600 cm-1, 500 cm-1 < y < 2000 cm-1, and 0.08 eV < t < 0.20 eV. Near isotropy of the optical properties of typical BEDT-TTF salts is confirmed by electrical transport studies. Rather small values of t are consistent with relatively low room-temperature conductivity. 

Fig. 6.1 Idealized linear chain with alternating transfer integrals r(l 5) and spring constants /f(l A) for double and single bonds, with 8 = A = 0.2. (a) Valence and conduction bands, Eq. (2), of the Hiickel chain Ho 8) with unit cell 2a, a = 1. (b) Optical and acoustical phonon frequencies, Eq. (3), of the chain the anomalous dispersion (dashed line) is for about 50% stronger e-ph coupling than in polyacetylene.

R, D. Jacobson, S. R. Wilson, G. A. Al-Jumaily, J. R, McNeil, and J. M. Bennett. Microstructure Characterization by Angle-Resolved Scatter and Comparison to Measurements Made by Other Techniques. To be published in AppL Opt. This work discusses the band width and modulation transfer function of the scatterometer, stylus profilometer, optical pro-filometer, and total integrated scattering systems, and gives results of mea suring several surhices using all techniques. 

---