Quantum Thermal Bath for Path Integral Molecular Dynamics Simulation

详细信息    查看全文

• 作者：Fabien Brieuc ; Hichem Dammak ; Marc Hayoun
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2016
• 出版时间：March 8, 2016
• 年：2016
• 卷：12
• 期：3
• 页码：1351-1359
• 全文大小：505K
• ISSN：1549-9626

文摘

The quantum thermal bath (QTB) method has been recently developed to account for the quantum nature of the nuclei by using standard molecular dynamics (MD) simulation. QTB-MD is an efficient but approximate method when dealing with strongly anharmonic systems, while path integral molecular dynamics (PIMD) gives exact results but in a huge amount of computation time. The QTB and PIMD methods have been combined in order to improve the PIMD convergence or correct the failures of the QTB-MD technique. Therefore, a new power spectral density of the random force within the QTB has been developed. A modified centroid-virial estimator of the kinetic energy, especially adapted to QTB-PIMD, has also been proposed. The method is applied to selected systems: a one-dimensional double-well system, a ferroelectric phase transition, and the position distribution of an hydrogen atom in a fuel cell material. The advantage of the QTB-PIMD method is its ability to give exact results with a more reasonable computation time for strongly anharmonic systems.