PNO–CI (pair natural orbital configuration interaction) and CEPA–PNO (coupled electron pair approximation with pair natural orbitals) calculations of molecular systems. II. The molecules BeH2, BH, BH3, CH4, CH−3, NH3 (planar and pyramidal), H2O, OH+3, HF and the Ne atom
PNO–CI (pair natural orbital configuration interaction) and CEPA–PNO (coupled electron pair approximation with pair natural orbitals) calculations of molecular systems. II. The molecules BeH2, BH, BH3, CH4, CH−3, NH3 (planar and pyramidal), H2O, OH+3, HF and the Ne atom
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分子系统的 PNO-CI（自然轨道构型相互作用）和 CEPA-PNO（自然轨道耦合电子对近似）计算 II。 )、H2O、OH+3、HF 和 Ne 原子
DOI：
10.1063/1.430638
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发表时间：
1975
影响因子：
3.5
通讯作者：
W. Kutzelnigg
中科院分区：
文献类型：
--
作者：
R. Ahlrichs;F. Driessler;H. Lischka;V. Staemmler;W. Kutzelnigg
PNO-CI和CEPA-PNO计算是针对分子MgH 2、AlH、AlH 3、SiH 4、PH 3、H2S、HCl和Ar原子进行的。使用了两种类型的高斯基集;两种基集都包含H上的一个p集。“小"集包括重原子上的一个d-集，”标准"基包括两个d-集和一个f-集。对于MgH 2和Ar，也使用“大"和”非常大“基，其包含额外的极化函数。分析了不同极化函数对能量的改善。估计了分子能量的Hartree-Fock极限。根据第一部分中定义的量，特别是根据IEPA（独立电子对）相关能eμIEPA和IEPA方案的误差ΔEIEPA，分析计算的价壳层相关能。如果采用定域表示，则价壳层轨道间对相关能和IEPA误差的绝对值都小于相应的第一行轨道间对相关能和IEPA误差。
PNO–CI and CEPA–PNO calculations are performed for the molecules MgH2, AlH, AlH3, SiH4, PH3, H2S, HCl, and the Ar atom. Two types of Gaussian basis sets are used; both sets contain one p‐set on H. The ’’small’’ set includes one d‐set on the heavy atom, the ’’standard’’ basis two d‐sets and one f‐set. Both for MgH2 and Ar, a ’’large’’ and a ’’very large’’ basis are used as well, which contain additional polarization functions. The energy improvement due to the different polarization functions is analyzed. Hartree–Fock limits for the molecular energies are estimated. The computed valence shell correlation energies are analyzed in terms of quantities defined in part I, in particular in terms of the IEPA (independent electron pair) correlation energies eμIEPA and the error ΔEIEPA of the IEPA scheme. Both the valence shell interorbital pair correlation energies and the IEPA error are smaller in absolute value than those of the corresponding first row hydrides, provided that one uses the localized representatio...