Group-based evaluation of temperature and pressure for molecular dynamics simulation with a large time step

Area of Science:

• Computational Chemistry
• Biophysics
• Materials Science

Background:

• Accurate temperature and pressure control are crucial for molecular dynamics (MD) simulations.
• Previous methods faced limitations in time step size (δt) under isothermal-isobaric conditions.
• Extending δt is essential for simulating larger systems and longer timescales.

Purpose of the Study:

• To improve isothermal-isobaric MD integration accuracy and performance.
• To introduce group-based evaluations for system temperature and pressure.
• To enable longer time steps in MD simulations, particularly for complex systems.

Main Methods:

• Developed group-based evaluations for system temperature and pressure.
• Integrated these evaluations into previous high-order MD integration schemes.
• Applied the improved scheme with velocity Verlet and r-RESPA integrators.
• Neglected high-frequency vibrational motions of hydrogen atoms for accuracy.

Main Results:

• Achieved conserved physical properties of lipid bilayer systems with extended time steps.
• Validated accuracy up to δt = 5 fs with velocity Verlet integrator.
• Validated accuracy up to δt = 3.5 fs for fast motions using r-RESPA.
• Demonstrated improved performance by avoiding thermostat/barostat iterations.

Conclusions:

• The enhanced group-based MD integration scheme significantly improves accuracy and performance.
• Longer time steps are now feasible for isothermal-isobaric simulations, including lipid bilayers.
• This advancement facilitates more efficient and accurate molecular simulations.