Best practices for second-generation Car-Parrinello ab initio molecular dynamics with CP2K/Quickstep

Second-generation Car–Parrinello $\mathit{\text{ab}}\mathit{\text{initio}}$ molecular dynamics (CP2G AIMD) combines a Born–Oppenheimer-like nuclear equation of motion with a predictor-corrector propagation of the one-particle density matrix and a modified Langevin equation to ensure an accurate sampling of the Boltzmann distribution. In the CP2K implementation, this approach can substantially reduce the number of self-consistent-field iterations required per molecular-dynamics step, but only if the density-matrix propagation, the orbital-transformation corrector, and the modified Langevin friction parameters are tuned consistently. This tutorial gives a practical workflow for setting up CP2G AIMD calculations in CP2K, starting from Born–Oppenheimer pre-equilibration and proceeding through corrector-step-size selection, always-stable predictor-corrector order optimization, final relaxation, and the calibration of the dissipative and stochastic terms used for canonical sampling. The protocol is demonstrated for a 32-molecule liquid-water benchmark and is written for users who already know the basics of CP2K input files but want a reliable route from a conventional AIMD setup to a production-ready CP2G simulation.