Ultra-violet band systems of silicon monoselenide and monotelluride

Abstract

Ultra-violet systems of red-degraded bands of SiSe and SiTe have been developed in heavy-current uncondensed discharges through silica tubes containing aluminium selenide and a mixture of aluminium and tellurium powders respectively. The vibrational analyses are described. The SiSe system consists of about thirty-five bands extending from λ2910 to λ3670 and has its 0->0 band at λ3089.3: the band-heads are approximately represented by ν = 32448.8 + (403.4u' - 3.24u'2 + 0.141u'3) - (580.0u'' - 1.78u''2 + 0.001u''3), where u = ν + ½. For SiTe, twenty-five bands have been measured between λ3290 and λ3900, the 0 -> 0 band being at λ3496.6, and the band-heads being represented by ν = 28663.5 + (335.7u' - 0.83u'2 - 0.080u'3) - (480.4u'' - 1.16u''2 - 0.008u''3). In neither case is the 0 -> 0 band very intense. These systems are analogous to the already known systems of SiO and SiS. The data are discussed briefly in relation to the corresponding systems of PbO, PbS, PbSe and PbTe, and other similar molecules of group-IVb elements.