MODELING OF NONLINEAR OPTIC AND ESR RESPONSE OF CDW MX MATERIALS

We report results on the nonlinear optic and ESR response of the PtX M X chain materials calculated using a discrete, 3/4-filled, two-band, t ight-binding Peierls-Hubbard model. We calculated electroabsorption (E A) spectra for the three PtX (X=Cl, Br, I) charge-density-wave (CDW) m aterials and find good agreement with the experimental data. We also o btain EA spectra for localized defects in PtBr. In addition, the field orientation dependence of the electron spin resonance spectra. associ ated with the spin carrying defects is calculated for PtX materials an d compared with ESR data on photoinduced defects.