Global potential energy surface of ground state singlet spin O.

A new global potential energy for the singlet spin state O system is reported using CASPT2/aug-cc-pVTZ ab initio calculations. The geometries for the six-dimensional surface are constructed using a novel point generation scheme that employs randomly generated configurations based on the beta distribution. The advantage of this scheme is apparent in the reduction of the number of required geometries for a reasonably accurate potential energy surface (PES) and the consequent decrease in the overall computational effort.

Dissociation cross sections for N + N → 3N and O + O → 3O using the QCT method.

Cross sections for the homo-nuclear atom-diatom collision induced dissociations (CIDs): N + N and O + O are calculated using Quasi-Classical Trajectory (QCT) method on ab initio Potential Energy Surfaces (PESs). A number of studies for these reactions carried out in the past focused on the CID cross section values generated using London-Eyring-Polanyi-Sato PES and seldom listed the CID cross section data. A highly accurate CASSCF-CASPT2 N and a new O global PES are used for the present QCT analysis and the CID cross section data up to 30 eV relative energy are also published.