Communication: Multiple-timestep ab initio molecular dynamics with electron correlation.

Area of Science:

• Computational Chemistry
• Theoretical Chemistry
• Molecular Dynamics

Background:

• Accurate molecular dynamics simulations require computationally expensive electronic structure calculations.
• Electron correlation effects in forces evolve slower than Hartree-Fock approximations.

Purpose of the Study:

• To develop a time-reversible, multiple-timestep protocol for ab initio molecular dynamics.
• To leverage the timescale differences between electron correlation and Hartree-Fock forces for efficiency gains.

Main Methods:

• Implementation of a multiple-timestep algorithm using short timesteps for Hartree-Fock and longer timesteps for Moøller-Plesset perturbation theory.
• Testing the protocol for ab initio molecular dynamics simulations with correlated wavefunction-based potentials.

Main Results:

• The developed protocol yields stable molecular dynamics trajectories.
• Significant relative speedups were achieved, comparable to force field-based multiple-timestep methods.
• Efficiency improvements are most pronounced for larger molecular systems.

Conclusions:

• The presented multiple-timestep protocol offers an efficient approach for ab initio molecular dynamics.
• This method provides a viable strategy for simulating larger systems with correlated electronic structures.