Density functional theory study of infrared and ultraviolet spectra of urea L-malic acid

Urea L-malic acid, a new second order nonlinear optical crystal, was studied using density functional theory (DFT). PBEPBE/6-31+G(d,p) method, the optimal method for comparing the results from the several DFT methods, was chosen to study the molecular structure. Infrared and ultraviolet-visible spectra were obtained and compared with experiments. The ultraviolet-visible spectrum was also analyzed by the molecular orbital population. The geometries, and the infrared and ultraviolet-visible spectra in water were studied using DFT methods in combination with the polarized continuum model to predict the perturbations by the solvent effect.