Analysis of vibrational spectra and nonlinear optical properties of organic molecule L-alaninium formate.

Vibrational and electronic spectra of the crystallized nonlinear optical molecule L-alaninium formate have been recorded and analyzed. The equilibrium geometry, vibrational wavenumbers, and the first order hyperpolarizability of the crystal have been calculated with the help of density functional theory computations. The N-H···O bond distance shows the presence of intramolecular hydrogen bonding and the result is confirmed by the natural bond orbital analysis. The HOMO-LUMO energy gap and the first order hyperpolarizability was calculated and it supports the nonlinear optical activity of the L-alaninium formate crystal.