Structural change of heavy water by laser-induced plasma generation

Stimulated Raman scattering (SRS) of –OD stretching vibration has been studied when laser-induced plasma is formed in heavy water by focusing an intense picosecond pulsed Nd:YAG laser beam (wavelength 532 nm, pulse duration 80 ps) at room temperature. The main peak of the SRS shows a remarkable blue-shift and an asymmetric intensity distribution. The Raman shift and active modes of the SRS indicate that the ice VII structure is formed and lasts 20–30 ps in the focal volume of the pumping beam in heavy water.