A quantum chemical determination of diabatic states

A simple electronic-structure-based construction of diabatic states from adiabatic states is formulated. It is accomplished by maximizing the configurational uniformity of the diabatic states with respect to the dominant configurations throughout the entire coordinate space. No configurational constraints are introduced. No matrix elements of additional, derivative, or nonderivative operators have to be calculated. The matrix elements between the diabatic states are simply expressible in terms of the adiabatic energies and wave function coefficients.