Abstract
Raman spectra of powder and single crystals of alpha silicon nitride have been measured at room temperature. More than twenty Raman lines were observed for annealed white powder samples and dominant lines were at 259, 365, 515, 668, 868, 915, 976, and 1034 cm−1. The former three lines were observed also for the single crystals in spite of strong fluorescence. These small wavenumber phonons could tentatively be assigned to collective vibration modes based on a reduction scheme for the irreducible representation of the space group of the crystal.