Theoretical calculation and vibrational spectral analysis of L-arginine trifluoroacetate

Fourier transform infrared and Raman spectra of the nonlinear optical crystal, L-arginine trifluoroacetate (L-arginine.CF3COOH, abbreviated as LATF) have been calculated by the first-principles calculation and investigated in experiment. The calculated results are slightly different from those experimental values because of the distinction resulted from the intermolecular hydrogen bonds. The role of this type of intermolecular interaction on the crystal vibrational spectra and nonlinear optical properties has been discussed. The absorption-edge on the IR side has been estimated by the theoretical approach on basis of the calculated infrared spectrum, which will be meaningful for further research on NLO crystal.