Extended Lagrangian free energy molecular dynamics

Abstract

Extended free energy Lagrangians are proposed for first principles molecular dynamics simulations at finite electronic temperatures for plane-wave pseudopotential and local orbital density matrix based calculations. Thanks to the extended Lagrangian description the electronic degrees of freedom can be integrated by stable geometric schemes that conserve the free energy. For the local orbital representations both the nuclear and electronic forces have simple and numerically efficient expressions that are well suited for reduced complexity calculations. A rapidly converging recursive Fermi operator expansion method that does not require the calculation of eigenvalues and eigenfunctions for the construction of the fractionally occupied density matrix is discussed. An efficient expression for the Pulay force that is valid also for density matrices with fractional occupation occurring at finite electronic temperatures is also demonstrated.

References in corpus (3)

• Time-reversible Born-Oppenheimer molecular dynamics
• An efficient and accurate decomposition of the Fermi operator
• Non-monotonic recursive polynomial expansions for linear scaling calculation of the density matrix

Cited by in corpus (5)

• First principles molecular dynamics without self-consistent field optimization
• Next generation extended Lagrangian first principles molecular dynamics
• Fast method for quantum mechanical molecular dynamics
• Canonical density matrix perturbation theory
• Extended Lagrangian Born-Oppenheimer molecular dynamics in the limit of vanishing self-consistent field optimization