REACTIONS OF SELENIUM IN A QUARTZ DISCHARGE-TUBE - INFRARED-SPECTRA AND DENSITY-FUNCTIONAL THEORY CALCULATIONS OF NEW SELENIUM-NITROGEN ANDSELENIUM-SILICON SPECIES IN SOLID ARGON

New selenium-nitrogen species were produced by condensing the effluent from an argon/nitrogen/selenium microwave discharge onto a 12 K subst rate. Nitrogen-15 and selenium-76 and -80 isotopic substitutions, phot olysis, and annealing provided basis for identification of the new pro duct absorptions in the infrared spectrum. A weak band at 951 cm(-1) i s assigned to SeN and the very strong 1019 cm(-1) band to v(3) of NSe2 radical with a 146 +/- 5 degrees valence angle. A new 1570 cm(-1) ban d in this system is due to the SeNO radical, and a 1771 cm(-1) absorpt ion, also made from Se-2 and NO, is due to the (SeSe)(NO) complex. Hig her-order SexNy (x > 1) species give rise to bands at 904, 736, 616, a nd 529 cm(-1). The argon/selenium discharge in quartz has also produce d the SiSe, SiSe2, and SeSiO species. Structure and frequency calculat ions using density functional theory support the matrix infrared ident ification of these new selenium molecular species. The most stable (NS e)(2) structure is calculated to be the cis form analogous to (NO)(2), but by contrast, (NSe)(2) has a stronger N=N bond and Se-Se bonding.