Quasi-Diabatic scheme for on-the-fly quantum dynamics propagation

We develop a nonadiabatic quantum dynamics scheme to interface diabatic quantum dynamics approaches with adiabatic electronic structure calculation. This scheme uses the crude adiabatic basis as a diabatic basis for a short-time nuclear dynamics propagation and updates it in each consecutive nuclear step. This scheme extends the scope and applicability of the diabatic quantum dynamics approaches and allows us to propagate on-the-fly quantum dynamics with them, avoiding any additional non-trivial efforts to perform diabatization or to formulate them back to the adiabatic representation. We combine Partial Linearized Density Matrix approach, a diabatic quantum dynamics method, with Density Functional Tight Binding, an electronic structure approach to demonstrate the applicability of our proposed scheme.