Static/dynamic first and second order hyperpolarizabilities, optimized structures, IR, UV-Vis, H and C NMR spectra for effective charge transfer compounds: A DFT study.

The effective charge transfer compounds, 4-N,N-dimethylamino-4'-N'-methyl-stilbazolium m-trifluoromethylbenzene-sulfonate (DSMFS) and 4-N,N-dimethylamino-4'-N'-methyl-stilbazolium p-trifluoromethylbenzene-sulfonate (DSPFS), were simulated in terms of geometric structure, IR, UV-Vis, H NMR and C NMR spectra. UV-vis spectra for both molecules give two peaks at 290 and 436 nm assigned as n-π* and π-π* transitions. The HOMO-LUMO energy gap for DSMFS (2.8174 eV) was calculated as lower than that of DSPFS (4.6649 eV). The detailed frontier molecular orbital analysis also indicated that the intra- and inter-molecular charge transfers occur in DSMFS and DSPFS. The static and dynamic (ω = 532 and 1064 nm) nonlinear optical properties were also investigated by using B3LYP/6-311++G(d,p) level. Static first and second order hyperpolarizabilities (β and γ) of DSMFS were obtained 1.5726 × 10 esu and 271.63 × 10 esu, and those for DSPFS were obtained as 1.5528 × 10 esu and 303.31 × 10 esu. The dynamic β and γ were obtained as higher than the static corresponding parameters. However, the increasing wavelength in dynamic NLO calculations led to a decrease in β and γ parameters.