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Abstract

In this paper we discuss theoretical investigations of UV- laserinduced desorption of NO-molecules from Nickeloxide- (100)-surfaces. We focus on the interpretation of experimental results (velocity-distributions of the desorbing molecules, rotational and vibrational distributions) by performing for the first time high quality ab initio configuration interaction calculations for the construction of 2D potential energy surfaces of the ground and excited states involved in the desorption process. We were able to characterize these states as charge transfer states, where an electron is transferred from the surface into the NO-2(pi) -orbital. Potential energy surfaces for the intermediate NO^--like states have been constructed by varying the molecule-surface distance and the tilt angle of the molecule axis with respect to the surface normal. The characterization of the potential energy surfaces allows for a mechanistic insight into the driving forces of nuclear motion. 3D wave packet calculations on the ab initio potential surfaces have been performed to simulate the experimentally obtained state resolved velocity distributions of the desorbing NO-molecules. It has been possible to simulate experimental details like desorption cross sections, bimodal velocity distributions and the coupling of rotational and translational degrees of freedom on the basis of our first principles calculations.