Structure, vibrational and electronic spectral studies of the SA−.AHMP+ crystal: A combined PXRD, FT-Raman, UV-Vis and DFT calculations.

During present work, the crystal of the organic salt (SA−.AHMP+) between salicylic acid and 2-amino-4- hydroxy-6-methylpyrimidine (AHMP) has been characterized using powder X-ray diffraction (PXRD), and FT-Raman. Then after, UV-Vis spectrum of SA−.AHMP+ is employed to estimate optical band gap using Tauc’s relation. The crystal structures and phase of the crystal have been investigated by combined analysis PXRD and Rietveld refinement. From PXRD analysis, cell parameters suggest that the SA−.AHMP+ belongs to orthorhombic structure. The vibrational signatures of the SA−.AHMP+ complex have been studied with the help of the Raman spectrum and DFT computation. The corrections in the vibrational frequencies at anharmonic oscillator approximation are made using the generalized second-order vibrational perturbation theory (GVPT2) at B3LYP/6-31G(d,p) level of theory. Moreover, nonlinear optical (NLO) properties of the SA−.AHMP+ complex are also studied at the same level of theory. [ABSTRACT FROM AUTHOR]