Faculty of Physics, University of Vienna, Kolingasse 14-16, 1090 Vienna, Austria.
Centre Européen de Calcul Atomique et Moléculaire (CECAM), Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
J Chem Phys. 2022 Dec 7;157(21):214110. doi: 10.1063/5.0130117.
A new algorithm for efficient and fully time-reversible integration of first-principles molecular dynamics based on orbital-free density functional theory (OFDFT) is presented. The algorithm adapts to this nontrivial case, the recently introduced Mass-Zero (MaZe) constrained dynamics. The formalism ensures that full adiabatic separation is enforced between nuclear and electronic degrees of freedom and, consequently, that the exact Born-Oppenheimer probability for the nuclei is sampled. Numerical integration of the MaZe dynamics combines standard molecular dynamics algorithms, e.g., Verlet or velocity Verlet, with the SHAKE method to impose the minimum conditions on the electronic degrees of freedom as a set of constraints. The developments presented in this work, which include a bespoke adaptation of the standard SHAKE algorithm, ensure that the quasilinear scaling of OFDFT is preserved by the new method for a broad range of kinetic and exchange-correlation functionals, including nonlocal ones. The efficiency and accuracy of the approach are demonstrated via calculations of static and dynamic properties of liquid sodium in the constant energy and constant temperature ensembles.
提出了一种新的算法，用于高效且完全时间可逆地整合基于无轨道密度泛函理论（OFDFT）的第一性原理分子动力学。该算法适用于最近引入的质量为零（MaZe）约束动力学这一复杂情况。该形式确保了核和电子自由度之间完全绝热分离，从而对核进行了精确的 Born-Oppenheimer 概率采样。MaZe 动力学的数值积分结合了标准的分子动力学算法，例如 Verlet 或速度 Verlet，以及 SHAKE 方法，以作为约束对电子自由度施加最小条件。本工作中的发展，包括对标准 SHAKE 算法的专门调整，确保了新方法在包括非局部的广泛动力学和交换相关泛函范围内保持 OFDFT 的准线性标度。通过在恒能和恒温系综中计算液态钠的静态和动态性质，证明了该方法的效率和准确性。
