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Multiple-time scale integration method based on an interpolated potential energy surface for ab initio path integral molecular dynamics
Ist Teil von
The Journal of chemical physics, 2024-04, Vol.160 (14)
Ort / Verlag
United States: American Institute of Physics
Erscheinungsjahr
2024
Quelle
American Institute of Physics (AIP) Journals
Beschreibungen/Notizen
A new multiple-time scale integration method is presented that propagates ab initio path integral molecular dynamics (PIMD). This method uses a large time step to generate an approximate geometrical configuration whose energy and gradient are evaluated at the level of an ab initio method, and then, a more precise integration scheme, e.g., the Bulirsch–Stoer method or velocity Verlet integration with a smaller time step, is used to integrate from the previous step using the computationally efficient interpolated potential energy surface constructed from two consecutive points. This method makes the integration of PIMD more efficient and accurate compared with the velocity Verlet integration. A Nosé–Hoover chain thermostat combined with this new multiple-time scale method has good energy conservation even with a large time step, which is usually challenging in velocity Verlet integration for PIMD due to the very small chain mass when a large number of beads are used. The new method is used to calculate infrared spectra and free energy profiles to demonstrate its accuracy and capabilities.