Adiabatic representation, vibrational modes

Single surface calculations with a vector potential in the adiabatic representation and two surface calculations in the diabatic representation with or without shifting the conical intersection from the origin are performed using Cartesian coordinates. As in the asymptotic region the two coordinates of the model represent a translational and a vibrational mode, respectively, the initial wave function for the ground state can be represented as. 

For a vibrational mode of the molecule to induce coupling between adiabatic electronic states p(r R), the direct product of the irreducible representations of < >.,(r R), p(r R), and the vibrational mode must contain the totally symmetric representation of the molecular point group,... 

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