Production and infrared absorption spectrum of ClSO2 in matrices

A new species, ClSO2, is produced and identified with infrared (IR) absorpt ion spectra when an argon or krypton matrix containing Cl-2 and SO2 is irra diated with laser emission at 355 nm. Lines at 1311.0, 1309.6, 1099.8, 1098 .2, 497,7, and 455.8 cm(-1) (or 1309.5, 1098.5, 497.0, and 454.2 cm(-1)) ar e assigned to ClSO2 isolated in solid Ar (or Kr). Assignments of IR absorpt ion lines are based on results of S-34 and O-18 isotopic substitution (in s olid Kr) and theoretical calculations. Theoretical calculations using densi ty-functional theories (B3LYP and B3P86 with an aug-cc-pVTZ basis set) were performed to predict the geometry, energy, vibrational frequencies, and in frared intensities of possible isomers of ClSO2: (pyramidal) ClSO2, cis-ClO SO, (nonplanar) ClOSO, and cis-ClSOO. Results predicted for pyramidal ClSO2 agree with observed experimental data. This is the first identification of ClSO2, which is presumably an important intermediate during photolysis of Cl2SO2 and in the reaction of Cl with SO2, especially at low temperatures, In addition to ClSO2, irradiation of the Cl-2/SO2/Ar matrix sample with las er light at 308 nm produces Cl2SO2. Possible mechanisms of formation are di scussed.