FTIR studies of O(3P) atom reactions with CSe2, SCSe, and OCSe

The overall rate coefficients of the reactions of CSe2, SCSe, and OCSe with O(P-3) atom have been determined to be k(CSe2) = (1.4 +/- 0.2) x 10(-10) cm(3) molecule(-1) s(-1), k(SCSe) = (2.8 +/- 0.3) x 10-(11) cm(3) molecule(-1) s(-1,) and k(OCSe) = (2.4 +/- 0.3) x 10(-11) cm(3) molecule(-1) s(-1) at 301-303 K using Fourier transform infrared (FTIR) absorption spectroscopy. The measurements have been accomplished by calibrating against the literature value of the rate coefficient for O(P-3) with CS2 (4 x 10(-12) cm(3) molecule(-1)s(-1)). A product channel giving OCSe in 32.0 +/- 4.2% yield has been found for the O + CSe2 reaction. Although CO was also detected, its generation could be attributed to subsequent reactions of OCSe with O atoms. The corresponding reaction for O + SCSe gives OCS and OCSe as observable products, with their yields given as 32.2 +/- 4.5 and 30.2 +/- 3.3%, respectively. Computational studies using UB3LYP/aug-cc=PVTZ methods have been used particularly to determine the reaction pathways for the channels in which OCS or OCSe is produced.