Department of Chemistry, New York University, New York, New York 10003, USA.
J Chem Phys. 2010 Nov 14;133(18):184110. doi: 10.1063/1.3499812.
The use of discrete variable representation (DVR) basis sets within ab initio molecular dynamics calculations allows the latter to be performed with converged energies and, more importantly, converged forces. In this paper, we show how to carry out ab initio molecular dynamics calculations in the isothermal-isobaric ensemble with fully flexible simulation boxes within the DVR basis set framework. In particular, we derive the appropriate DVR based expression for the pressure tensor when the electronic structure is represented using Kohn-Sham density functional theory, and we examine the convergence of this expression as a function of the basis set size. An illustrative example using 64 silicon atoms in a fully flexible box using a combination of the Martyna-Tobias-Klein [Martyna et al., J. Chem. Phys. 101, 4177 (1994)] and Car-Parrinello [Car and Parinello, Phys. Rev. Lett. 55, 2471 (1985)] algorithms is presented to demonstrate the efficacy of the approach.
在从头算分子动力学计算中使用离散变量表示 (DVR) 基组可以使后者以收敛的能量进行计算，更重要的是，可以使收敛的力进行计算。在本文中，我们展示了如何在 DVR 基组框架内使用完全灵活的模拟盒在等温和等压系综中进行从头算分子动力学计算。具体来说，我们推导出了在使用 Kohn-Sham 密度泛函理论表示电子结构时压力张量的适当 DVR 表达式，并研究了该表达式随基组大小的收敛性。通过使用 Martyna-Tobias-Klein [Martyna 等人，J. Chem. Phys. 101, 4177 (1994)] 和 Car-Parrinello [Car 和 Parinello，Phys. Rev. Lett. 55, 2471 (1985)] 算法的组合，使用 64 个硅原子在完全灵活的盒子中进行了说明性示例，以证明该方法的有效性。
