title: On the role of the simplest S-nitrosothiol, HSNO, in atmospheric and biological processes.
abstract: Using state-of-the-art theoretical methods, we investigate the lowest electronic states of singlet and triplet spin multiplicities of HSNO. These computations are done using configuration interaction ab initio methods and the aug-cc-pV5Z basis set. One-dimensional cuts of the six-dimensional potential energy surfaces of these electronic states along the HS, SN stretches and HSN, SNO bending and torsion coordinates are calculated. Several avoided crossings and conical intersections are found. We computed also radiative lifetimes and spin-orbit couplings of these electronic states. Our work shows that the dynamics on these excited states is very complex, and suggest that multi-step mechanisms will populate the ground state via radiationless processes or lead to predissociation or intramolecular isomerization. For instance, these potentials are used to propose mechanisms for the IR, Vis, and UV light-induced cis-trans interconversions of HSNO and reactivity towards HS + NO and H + SNO products. Our findings are in good agreement with previous experimental studies on the photochemistry of HSNO. The atmospheric implication of HSNO is also discussed.
authors.affiliation: Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée, France.
authors.forename: Majdi
authors.initials: M
authors.lastname: Hochlaf
authors.affiliation: Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée, France.
authors.forename: Roberto
authors.initials: R
authors.lastname: Linguerri
authors.affiliation: Department of Chemistry and Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47906, USA.
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Francisco
mesh_terms: D001686:Biological Phenomena / Q000502:physiology; D003198:Computer Simulation; D020030:Nitric Oxide Donors / Q000737:chemistry; D026403:S-Nitrosothiols / Q000737:chemistry*
chemical_list: D020030:Nitric Oxide Donors; D026403:S-Nitrosothiols