1 Centre for Research in Molecular Modeling, and Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec, Canada H4B 1R6.

High-level ab initio calculations employing the CCSD and CCSD(T) coupled cluster methods with a series of systematically convergent correlation-consistent basis sets have been performed to obtain accurate molecular geometry and energetic properties of the simplest S-nitrosothiol (RSNO), HSNO. The properties of the S-N bond, which are central to the physiological role of RSNOs in the storage and transport of nitric oxide, are highlighted. Following corrections for quadruple excitations,...