Study on the behavior of energy convergence in ab initio crystal orbital calculations
Study on the behavior of energy convergence in ab initio crystal orbital calculations
复制标题
从头算晶体轨道计算中能量收敛行为的研究
DOI：
10.1007/bf00186446
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
H. Teramae
中科院分区：
文献类型：
--
作者：
H. Teramae
本文研究了在没有长程修正的情况下，从头晶轨道计算对截断方案的依赖性。通过对聚乙烯和LiH链的计算，我们深入研究了纳穆尔截止和胞格截止方案。纳穆尔截止给出了相对于邻居数（N 0）的最快能量收敛。关于N 0的能量收敛行为取决于基组。纳穆尔截止显示与STO-3G基组的最快收敛，与MINI基组的中等收敛，以及与（7s 4p/3s）基组的最慢收敛。单元格截断值正好与纳穆尔截断值的顺序相反。纳穆尔截止破坏了平移对称性。纳穆尔截断和胞格截断方案在用C2 H4单胞计算时，在聚乙烯的两个等价C-C键上引入轻微的不对称性。略微增加N 0可以使与纳穆尔截止的不对称性消失。对两种不同的反式聚乙炔晶胞结构的计算表明了截止方案对总能量的影响。只有对称截止能量是相同的。与纳穆尔截止相关的不一致在N 0 = 20时消失，然而，与单元式和修改的对称截止方案相关的不一致在N 0 = 20时保持。优化的几何形状和振动频率是不敏感的截止方法，除了与对称截止。所有结果的汇编表明，当使用最小基集（尤其是STO-3G基集）计算绝缘体时，纳穆尔截止是上级截止方案。
This article studies the dependence on the cutoff scheme ofab initiocrystal orbital calculations with no long-range correction. We have thoroughly studied the Namur cutoff and cell-wise cutoff schemes through calculations of polyethylene and LiH chains. The Namur cutoff gives the fastest energy convergence with respect to the number of neighbors (N0). The energy convergence behavior with respect toN0depends on the basis set. The Namur cutoff shows the fastest convergence with the STO-3G basis set, intermediate convergence with the MINI basis set, and the slowest convergence with the (7s4p/3s) basis set. The cell-wise cutoff shows exactly the reverse order of the Namur cutoff. The Namur cutoff destroys the translational symmetry. Both the Namur cutoff and cell-wise cutoff schemes introduce slight asymmetry on the two equivalent C-C bonds of polyethylene when calculating with a C2H4unit cell. The asymmetry with the Namur cutoff can be made to disappear by increasingN0a little. The calculations on two different unit-cell structures oftrans-polyacetylene show the effect of the cutoff scheme on the total energy. Only the symmetric cutoff energies are the same. Disagreement related to the Namur cutoff disappears atN0= 20, however, that related to the cell-wise and modified symmetric cutoff schemes remains atN0⩽ 20. The optimized geometry and vibrational frequency are not as sensitive to the cutoff method except with the symmetric cutoff. A compilation of all results shows that the Namur cutoff is the superior cutoff scheme when calculating the insulator using the minimal basis set, especially the STO-3G basis set.