Toward the modeling of the NO 2 ( 2 A ″ ) manifold

Global diabatization angles are obtained to construct a 3 × 3 diabatic potential matrix for the 2 A ″ states of NO 2 . Over 12,500 energies have been calculated to map ab initio, the configuration space of (at least) the first 3 adiabatic sheets. With the level of theory used, such angles could be modeled such as to ensure a proper description of all involved crossing seams as well as the merging of the diabats into the adiabats at the asymptotic limits. This result provides an extension to the 3‐state case of the method proposed earlier (Mota and Varandas, J Phys Chem A 2008, 112, 3768), and illustrates the essential steps toward the modeling of the NO 2 ( 2 A ″ ) manifold via double many‐body expansion theory. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011