GROUND-STATE POTENTIAL-ENERGY SURFACE OF HNS-NSH SYSTEMS - A DENSITY-FUNCTIONAL STUDY

Density functional theory (DFT) calculations have been made to study t he potential energy surface of HNS system. Calculated equilibrium geom etries of HNS, NSH and the transition state (TS) are in good agreement with the results of other high level ab-initio studies. HNS is predic ted to be more stable than NSH (25 kcal mol(-1)). The energy barrier f or the isomerization of HNS to NSH is predicted to be 70 kcal mol(-1). Calculated atomization energies, vibrational frequencies, and zero po int vibrational energies are in excellent agreement with other estimat es. The adequacy of the functional used here has also been tested by e xamining the results for HCN-HNC systems for which both experimental a nd high quality ab-initio results are available in the literature.