Pierleoni Carlo, Ceperley David M
Department of Physics, University of L'Aquila, Via Vetoio, 67010 L'Aquila, Italy.
Chemphyschem. 2005 Sep 5;6(9):1872-8. doi: 10.1002/cphc.200400587.
In the last few years, we have been developing a Monte Carlo simulation method to cope with systems of many electrons and ions in the Born-Oppenheimer approximation: the coupled electron-ion Monte Carlo method (CEIMC). Electronic properties in CEIMC are computed by quantum Monte Carlo rather than by density functional theory (DFT) based techniques. CEIMC can, in principle, overcome some of the limitations of the present DFT-based ab initio dynamical methods. The new method has recently been applied to high-pressure metallic hydrogen. Herein, we present a new sampling algorithm that we have developed in the framework of the reptation quantum Monte Carlo method chosen to sample the electronic degrees of freedom, thereby improving its efficiency. Moreover, we show herein that, at least for the case of metallic hydrogen, variational estimates of the electronic energies lead to an accurate sampling of the proton degrees of freedom.
在过去几年中，我们一直在开发一种蒙特卡罗模拟方法，以处理处于玻恩-奥本海默近似下的多电子和离子系统：耦合电子-离子蒙特卡罗方法（CEIMC）。CEIMC中的电子性质是通过量子蒙特卡罗方法计算的，而不是基于密度泛函理论（DFT）的技术。原则上，CEIMC可以克服当前基于DFT的从头算动力学方法的一些局限性。这种新方法最近已应用于高压金属氢。在此，我们提出一种新的采样算法，该算法是在用于对电子自由度进行采样的蠕动量子蒙特卡罗方法框架内开发的，从而提高了其效率。此外，我们在此表明，至少对于金属氢的情况，电子能量的变分估计导致对质子自由度的精确采样。
