A practical ansatz for evaluating the electronic friction tensor accurately, efficiently, and in a nearly black-box format

It is well-known that under conditions of fast electronic equilibration and weak nonadiabaticity, nonadiabatic effects induced by electron-hole pair excitations can be partly incorporated through a frictional force. However, ab initio computation of the electronic friction tensor suffers from numerical instability and usually demands a convergence check. In this study, we present an efficient and accurate interpolation method for computing the electronic friction tensor in a nearly black-box manner as appropriate for molecular dynamics. In almost all cases, our method agrees quite well with the exact friction tensor which is available for several quadratic Hamiltonians. As such, we outperform more conventional approaches that are based on the introduction of a broadening parameter. Future work will implement this interpolation approach within ab initio software packages.