First principles molecular dynamics without self-consistent field optimization.

Area of Science:

• * Computational Chemistry
• * Quantum Mechanics
• * Materials Science

Background:

• * Ab initio molecular dynamics (AIMD) simulations are crucial for understanding chemical reactions and material properties.
• * Traditional AIMD methods often require computationally expensive self-consistent field (SCF) optimizations at each step.
• * Born-Oppenheimer molecular dynamics (BoDynamics) provides a robust framework but can be computationally intensive.

Purpose of the Study:

• * To present a novel optimization-free AIMD approach.
• * To reduce the computational cost of AIMD simulations.
• * To enable accurate simulations of molecular dynamics, especially for systems with complex electronic structures.

Main Methods:

• * Developed an extension of time-reversible extended Lagrangian Born-Oppenheimer molecular dynamics.
• * Implemented the method in the limit of vanishing self-consistent field (SCF) optimization.
• * Derived the dynamics for a general free-energy potential surface at finite electronic temperatures within hybrid density functional theory (DFT).

Main Results:

• * The optimization-free dynamics significantly minimizes computational cost.
• * Molecular trajectories closely follow the exact Born-Oppenheimer potential energy surface.
• * Requires only a single diagonalization and Hamiltonian construction per time step.
• * Provides a stable starting point for more complex iterative optimizations.

Conclusions:

• * The proposed optimization-free dynamics offers a computationally efficient AIMD framework.
• * It is suitable for a broad range of ab initio molecular dynamics simulations.
• * Represents a flexible theoretical advancement for studying molecular systems.