A New Method for Treating Drude Polarization in Classical Molecular Simulation.

Area of Science:

• Computational chemistry
• Molecular dynamics
• Quantum chemistry

Background:

• Accurate calculation of many-body polarization is crucial for molecular simulations.
• Existing methods for polarization calculations can be computationally expensive or unstable.
• The Drude oscillator model is a common approach for simulating polarizable systems.

Purpose of the Study:

• To extend the inertial extended Lagrangian, self-consistent field iteration-free (iEL/0-SCF) method to the Drude oscillator model.
• To improve the efficiency and stability of molecular dynamics simulations involving polarization.
• To enable longer integration time steps in simulations of polarizable systems.

Main Methods:

• The inertial extended Lagrangian, self-consistent field iteration-free (iEL/0-SCF) method was adapted for the Drude oscillator model.
• The method was applied to the polarizable simple point charge model (PSPC) for water.
• Stability and performance were compared to traditional extended Lagrangian (EL) methods.

Main Results:

• The iEL/0-SCF method demonstrated stability comparable to well-converged self-consistent field (SCF) solutions.
• It proved more stable than traditional EL approaches and two-temperature ensemble formulations.
• The method eliminated the need for mass repartitioning and conserved linear and angular momentum.
• An integration time step of 6.0 fs was achieved for PSPC water simulations.

Conclusions:

• The iEL/0-SCF method offers a stable and efficient approach for calculating many-body polarization with Drude oscillators.
• This advancement allows for significantly longer time steps in molecular dynamics simulations.
• The method provides a robust alternative to existing polarization calculation techniques.