Raman and Coherent Raman Symmetry Specific Low-Frequency Vibrational Spectra of Crystals*

Polarization-selected molecular and phonon vibrational spectra of crystals provide vital information about the symmetry properties of crystal systems. The measurement methods are well established in laser spontaneous Raman spectroscopy. Coherent Raman spectroscopy methods still lack the widely accepted measurement and terminology procedures because of the complexity of the methods and data processing.  We will explain the crucial details of the coherent methods and the experimental challenges needed to determine the symmetry properties of the crystals. We measured the vibrational spectra of single crystals ( CARS and 3CBCRS [1]) belonging to the cubic and trigonal systems.  We have concluded that the coherent Raman methods can complement the spontaneous Raman polarization-sensitive results.

[1] Spectrochim. Acta-Part A , (1999) (2018) 448-454