Spontaneous and stimulated Raman scattering by the products of the interaction of lithium deuteride with the environment

The processes of spontaneous and multicomponent stimulated Raman scattering (SRS) in a polycrystal consisting of the products of the interaction of lithium deuteride crystals with air molecules are studied. The interaction of lithium deuteride with environmental molecules resulted in a solid polycrystalline mixture of LiOH, LiOD, LiOH·H2O, and Li2CO3 on the crystal surface. Excitation of the sample under study by the third harmonic of a picosecond repetitively pulsed YAG:Nd3+ laser made it possible to detect three Stokes and the second anti-Stokes SRS components with a Raman frequency ν = 3660 cm−1 corresponding to the valence breathing mode of the OH− ion. A feature of the obtained spectra is the smaller spectral half-width of the second and third Stokes components compared to the first. When the studied polycrystals were excited by picosecond radiation with a wavelength λ = 532 nm, two Stokes and one anti-Stokes SRS components corresponding to the internal symmetric vibrational mode of LiOH were detected. The excitation of SRS at the Raman frequency of the OH− vibration ν = 3660 cm−1 in solids is promising due to the high-frequency shift and high quality factor, and is also important for studying the strength of hydrogen bonds.