The enthalpy of formation of the HSO radical revisited

The enthalpy of formation of the HSO and SOH radicals has been determined employing the CCSD(T) methodology with the aug-cc-pV(X+d)Z basis sets X = D,T,Q,5. Our best estimations are DeltaH(f,298)(0)(HSO) = -5.2 +/- 0.5 and DeltaH(f,298)(0) (SOH) = - 1.6 +/- 0.5 kcal/mol. The procedure employed to determine those values involves, extrapolation to the CBS limit, a correction for core-valence and relativistic effects. This result is in reasonable agreement with our previous estimations [Int. J. Quant. Chem. 80 (2000) 439] -6.6 and -1.6 kcal/mol for HSO and SOH, respectively. However, it is larger than the lower bound recently estimated by Balucani et al. [JPC. 120 (2004) 9571] -3.0 kcal/mol at 0 K (-3.7 kcal/mol at 298 K). (C) 2004 Elsevier B.V. All rights reserved.