A new ab initio potential energy surface of HCN(1(1)A '') and the predissociative resonances of HCN and DCN

We report a new three-dimensional ab initio potential energy surface of the first excited singlet (1(1)A ") state of HCN. More than one thousand poten tial points have been calculated at the multi-reference configuration inter action level employing a large basis set. Variational calculations of the p redissociative resonances of both HCN and DCN are performed on the three-di mensional spline fitted potential energy surface, which yield both position s and widths. Fairly good agreement with experiment confirms the accuracy o f our new potential energy. These resonances provide valuable information o n the photodissociation dynamics of HCN/DCN in the 1(1)A " state. (C) 2001 Elsevier Science B.V. All rights reserved.