Optical spectroscopy of scintillations occurring in unirradiated glycine and triglycine sulfate:L-alanine

Several research groups have reported observations of scintillations in well-known ferroelectric crystals. Previously we reported similar activity occurring in unirradiated glycine (nonferroelectric) but did not report the optical spectrum associated with the scintillations. In this paper we present the optical-spectroscopy results for scintillations occurring in single crystals of glycine and $L$-alanine-doped triglycine sulfate (LATGS). Seven lines were identified in glycine and eight lines in LATGS, all belonging to the second positive system of ${\mathrm{N}}_2$. The spectrum results from an electrical discharge from the crystal surface, which has a layer of ${\mathrm{N}}_2$ adsorbed onto it, to ground.