A comparison of Car—Parrinello and Born—Oppenheimer generalized valence bond molecular dynamics

Two methods for performing ab initio molecular dynamics using a generalized valence bond electronic wave function are compared: the Car—Parrinello and Born—Oppenheimer approaches. These techniques differ in how they generate a new electronic wave function at each time step. In the Car—Parrinello scheme, the wave function parameters are propagated as classical degrees of freedom, while in the Born—Oppenheimer scheme the equations describing the wave function are solved at each time step. It is found that trajectories obtained utilizing the Born—Oppenheimer approach are both more accurate and less costly than their Car—Parrinello counterparts for wave functions expressed in terms of atom-centered basis sets.