High-accuracy DMBE potential energy surface for CNO(A''4) and the rate coefficients for the C + NO reaction in the A'2, A''2, and A''4 states.

An accurate potential energy surface (PES) for the lowest lying A''4 state of the CNO system is presented based on explicitly correlated multi-reference configuration interaction calculations with quadruple zeta basis set (MRCI-F12/cc-pVQZ-F12). The ab initio energies are fitted using the double many-body expansion method, thus incorporating long-range energy terms that can accurately describe the electrostatic and dispersion interactions with physically motivated decaying functions. Together with the previously fitted lowest A'2 and A''2 states using the same theoretical framework, this constitutes a new set of PESs that are suitable to predict rate coefficients for all atom-diatom reactions of the CNO system.

HN2(2A') electronic manifold. II. Ab initio based double-sheeted DMBE potential energy surface via a global diabatization angle.

A double-sheeted double many-body expansion potential energy surface is reported for the coupled 12A'/22A' states of HN2 by fitting about 6000 ab initio energies. All crossing seams are described to their full extent on the basis of converged results. The lowest adiabatic sheet is fitted with a rmsd of 0.

HN2(2A') electronic manifold. I. A global ab initio study of first two states.

A detailed ab initio multireference configuration interaction calculation with a standard aug-cc-pVTZ basis set is reported for the 1(2)A' and 2(2)A' states of the title system. The aim is to establish the dissociation scheme of all channels, while revealing the 2(2)A'/3(2)A' seam of conical intersections consistent with the crossings in the diatomic fragments. An ab initio mapping of linear NNH and T-shaped and linear NHN loci of conical intersections is also reported, jointly with a discussion of the topological features associated to a newly reported 2(2)A'/3(2)A' crossing seam.