高等学校化学学报 ›› 1999, Vol. 20 ›› Issue (12): 1916.

• 论文 • 上一篇    下一篇

自优化扩散量子Monte Carlo差值法

黄宏新1, 严超1, 张小菊1, 曹泽星2   

  1. 1. 湖南师范大学化学系, 长沙 410081;
    2. 厦门大学化学系, 厦门 361005
  • 收稿日期:1998-12-23 出版日期:1999-12-24 发布日期:1999-12-24
  • 通讯作者: 黄宏新,男,49岁,教授.
  • 作者简介:黄宏新,男,49岁,教授.
  • 基金资助:

    国家自然科学基金(批准号:29773036);湖南省教委科研基金资助课题

Differential Diffusion Quantum Monte Carlo Method

HUANG Hong-Xin1, YAN Chao1, ZHANG Xiao-Ju1, CAO Ze-Xing2   

  1. 1. Department of Chemistry, Hunan Normal University, Changsha 410081, China;
    2. Department of Chemistry, Xiamen University, Xiamen 361005, China
  • Received:1998-12-23 Online:1999-12-24 Published:1999-12-24

摘要: 提出了自优化扩散量子MonteCarlo差值法,这是一个集优化、扩散和相关取样三项技术于一身的MonteCarlo新算法.这个算法能够在扩散过程中直接计算两个体系之间的能量差,且使计算结果的统计误差达到10-5hartree数量级,获得相关能达80%以上.应用该方法研究分子势能面,使用"刚性移动"模型,利用Jacobi变换使分子两个几何构型的能量计算具有很好的正相关性,因而能得到准确的能量差值和分子势能面.另外,我们还首创了"平衡后留样"技术,可节省50%以上的计算量.该算法还可应用于分子光谱、化学反应能量变化值等领域的研究.

关键词: 差值法, 量子Monte Carlo方法, 相关取样, 势能面

Abstract: Adifferential approach for self-optimizing diffusion quantum Monte Carlo calculation was proposed in this paper, which is a new algorithm combining with three techniques such as optimizing, diffusion and correlation sampling. This method can directly be used to calculate the energy differential between two systems in the diffusion process, make the statistical error of calculation reduce to the order of 10-5hartree, and recover about more than 80% of the correlation energy. We employed this approach to set up a potential energy surface of a molecule, used a "rigid move" model, and utilized Jacobi transformation to make energy calculation for two configurations of a molecule have a good positive correlation. So, an accurate energy differential could be obtained, and the potential energy surface with a good quality can be depicted. In the calculation, a technique called "post-equilibrium remaining sample" was set up firstly, which can save about 50% of computation expense. This novel algorithm can also be applied to studying other related fields such as molecular spectroscopy and the energy variation in chemical reactions.

Key words: Differential approach, Quantum Monte Carlo method, Correlation sampling, Potential energy surface

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