Accurate molecular dynamics and nuclear quantum effects at low cost by multiple steps in real and imaginary time: using density functional theory to accelerate wavefunction methods

Understand

The development and implementation of increasingly accurate methods for electronic structure calculations mean that, for many atomistic simulation problems, treating light nuclei as classical particles is now one of the most serious approximations.

• Even though recent developments have significantly reduced the overhead for modelling the quantum nature of the nuclei, the cost is still prohibitive when combined with advanced electronic structure methods.
• Here we present how multiple time step integrators can be combined with ring-polymer contraction techniques (effectively, multiple time stepping in imaginary time) to reduce virtually to zero the overhead of modelling nuclear quantum effects, while describing inter-atomic forces at high levels of electronic structure theory.
• This is demonstrated for a combination of MP2 and semi-local DFT applied to the Zundel cation.