【摘要】 提出了固定节面量子MonteCarlo的一个新方法 ,与传统的固定节面法相比 ,这个新方法能更准确地计算分子的能量 .导出了系统能量本征值的一个展开式 ,证明传统固定节面法所求出的能量值仅仅是能量本征值的零级近似 ;而新方法可以在只增加很少计算量 (小于 1% )的情况下 ,方便地求出一级近似、二级近似……给出了该方法的具体计算公式和步骤 ,并用它处理了H2 ,LiH ,Li2 和H2 O分子的基态能 .计算结果表明 ,对这些分子的基态只需要二级近似即可获得 97%以上的电子相关能 .说明新方法在准确度和计算量两个方面都是非常卓越的更多还原

【Abstract】 A new algorithm of the Fixed-node quantum Monte Carlo is reported in this paper. It is more accurate for the calculation of the molecule energies than the conventional Fixed-node quantun Monte Carlo processes. A develop formula of the energy eigenvalue of the system is deduced in th text. It is proved that the conventional Fixed-node energy is only the zeroth-order-approximation of the energy eigenvalue of the system. the first(or second……)order-approximation of the energy eigenvalue can be conveniently calculated by this new algorithm, with but very little increase in computational cost(under 1%). The computation formulas and concrete procedures of this algorithm are presented in this paper. This new algorithm is used to compute the energies of the ground states for molecules H 2, LiH, Li 2 and H 2O. The calculated results show that the energy values of the molecules after only the third-order-approximation can achieve over 98% of the correlation energy, indicating that the new algorithm is very superior in both accuracy and computational cost.更多还原