Electronic spectrum of atomic sulfur in argon matrices in the vacuum ultraviolet region

S atoms have been generated through vacuum ultraviolet photolysis of carbonyl sulfide (OCS) in Ar matrices. Excitation spectra measured by monitoring the 1S→1D emission of S at 784 nm are assigned to Ar+S−←ArS charge-transfer (CT) (135 nm, substitutional site (SS) and 159 nm, interstitial site (IS)) and 3S←3P Rydberg (160.8 nm) transitions. Empirically derived potential curves of Rg+S− and Rg+O− species predict the transition energies with reasonable accuracy. S atoms are found to be more photomobile than O atoms in Ar matrices.