VIBRATIONAL SPECTROSCOPIC STUDY OF L-ARGININE PHOSPHATE MONOHYDRATE (LAP), A NEW ORGANIC NONLINEAR CRYSTAL

L-Arginine phosphate monohydrate (LAP) is a recently discovered organic non-linear crystal which has the potential to replace a conventional crystal such as potassium dihydrogen phosphate. The polarized Raman and infrared spectra of a single crystal of LAP have been recorded to determine the symmetries of the molecular vibrations. The lattice lines are fairly strong compared with the others and show pronounced intensity variations with the orientation of the crystal. The high-frequency lines are assigned to the vibrations of the various molecular groups such as NH3+, NH2+, NH2, CH2, CH, COO-, H2O and H2PO4- present in the crystal.