Raman spectroscopic and theoretical study of liquid and solid water within the spectral region 1600-2300 cm−1

The mystery of the unusually high relative Raman intensity of the water line near 2200 cm−1 was in the focus of this investigation. To find the Raman intensity of the librational and bending combined vibration of water, 2D PES and 2D surfaces of the polar tensor components were calculated using natural rocking and bending coordinates. The possible impact of the large-amplitude motion in this vibration on the intensity of the 2200 cm−1 line was analyzed.282