On subjecting either CS2 or sulphur vapour in flowing neon to microwave discharge and collecting the products, we formed dilute deposits of S2+ in solid Ne near 5 K. The photoluminescence of S2+ in the system A 2Πu → X 2Πg was measured in the wavelength range 450-800 nm, and isotopically enriched samples of 34S2+ and 32S34S+ yielded unambiguous vibrational assignments; for 32S2+ up to v″ = 12, ṽ00 = (22260.8 ± 1.4), Y″1,0 = (809.0 ± 0.6) and Y″2,0 = - (3.50 ± 0.04) cm-1. In these photoluminescence spectra, two distinct progressions with separation insensitive to nuclear mass are observed, involving spin-orbital substates of the electronic ground state; the value of the spin-orbital coupling parameter A″0 is (493 ± 2) cm-1. Excitation spectra in the region 330-430 nm exhibited for 32S2+ a progression up to v′=15 with Y′,1,0 = (556.0 ± 0.4) and Y′2,0 = - (3.21 ± 0.03) cm-1. With improved resolution, the splitting of most lines into doublets or triplets is attributed to the effects of S2+ in solid neon, being trapped in sites of multiple character. We compare our results for trapped 32S2+ with those reported for free 32S2+ in the gaseous phase, and discuss the spectral consequences of the confinement of species trapped by surrounding Ne atoms.
|Number of pages||9|
|Journal||Spectrochimica Acta - Part A Molecular Spectroscopy|
|State||Published - 30 Nov 1996|
- Matrix isolation
- Vibronic transition