Time-dependent density-functional theory method in the electron nuclear dynamics framework

A time-dependent density-functional theory (DFT) dynamics method in the electron nuclear dynamics (END) framework is presented. This time-dependent variational method treats simultaneously the nuclei and electrons of a system without utilizing predetermined potential energy surfaces. Like the simplest-level END, this method adopts a classical-mechanics description for the nuclei and a Thouless single-determinantal representation for the electrons. However, the electronic description is now expressed in a Kohn–Sham DFT form that provides electron correlation effects absent in the simplest-level END. Current implementation of this method employs the adiabatic approximation in the exchange–correlation action and potential. Simulations of molecular vibrations and proton–molecule reactions attest to the accuracy of the present method.