Car-Parrinello molecular dynamics with Vanderbilt ultrasoft pseudopotentials

We show how the ultrasoft pseudopotentials which have recently been proposed by Vanderbilt can be implemented efficiently in the context of Car-Parrinello molecular-dynamics simulations. We address the differences with respect to the conventional norm-conserving schemes, identify certain problems which arise, and indicate how these problems can be overcome. This new scheme extends the possibility of performing first-principles molecular dynamics to systems including first-row elements and transition metals.