高氯酸HClO $_4$和高氯酸酐Cl $_2$ O $_7$的生成热。对W1和W2理论局限性的探讨
Heats of formation of perchloric acid, HClO$_4$, and perchloric anhydride, Cl$_2$O$_7$. Probing the limits of W1 and W2 theory
摘要：
用W_1和W_2理论首次测定了HClO $_4$和ClPDMATHABMN O $_7$的生成热。这些分子表现出特别严重的内极化程度，因此获得总原子化能量的基础设定极限SCF分量成为一个挑战。（将高指数$d$函数添加到标准$spd$基组对Cl $_2$ O $_7$的影响约为100 kcal/mol。）Wilson的aug-cc-pV（n+d）Z基组比标准aug-cc-pVnZ基组有了显著的改进，而aug-cc-pVnZ+2d 1f序列收敛得更快。Jensen的极化一致基组仍然需要额外的高指数$d$函数：为了光滑收敛，我们建议采用aug-pc 1 +3d，aug-pc 2 +2d，aug-pc 3 +d，aug-pc 4序列.紧$d$功能的作用被证明是一个改进的描述的Cl（3d）里德伯轨道，提高其能力，从氧孤对接收背键。在像这样有问题的情况下（或实际上一般情况下），单个SCF/aug-cc-pV 6 Z +2d 1f计算可能优于经验驱动的外推。我们对生成热的最佳估计是$ΔH^\circ_{f,298}[$ HClO $_4$（g）$]=-0.6\pm$ 1 kcal/mol和$ΔH^\circ_{f,298}[$ Cl $_2$ O $_7$（g）$]=65.9\pm$ 2 kcal/mol，最大的不确定性来源是我们无法解释CCSD（T）后的相关效应。虽然G2和G3理论有相当大的误差，但G3 X理论将两个值都再现到2 kcal/mol以内。
英文摘要：
The heats of formation of HClO$_4$ and Cl$_2$O$_7$ have been determined to chemical accuracy for the first time by means of W1 and W2 theory. These molecules exhibit particularly severe degrees of inner polarization, and as such obtaining a basis-set limit SCF component to the total atomization energy becomes a challenge. (Adding high-exponent $d$ functions to a standard $spd$ basis set has an effect on the order of 100 kcal/mol for Cl$_2$O$_7$.) Wilson's aug-cc-pV(n+d)Z basis sets represent a dramatic improvement over the standard aug-cc-pVnZ basis sets, while the aug-cc-pVnZ+2d1f sequence converges still more rapidly. Jensen's polarization consistent basis sets still require additional high-exponent $d$ functions: for smooth convergence we suggest the \{aug-pc1+3d,aug-pc2+2d,aug-pc3+d,aug-pc4\} sequence. The role of the tight $d$ functions is shown to be an improved description of the Cl (3d) Rydberg orbital, enhancing its ability to receive back-bonding from the oxygen lone pairs. In problematic cases like this (or indeed in general), a single SCF/aug-cc-pV6Z+2d1f calculation may be preferable over empirically motivated extrapolations. Our best estimate heats of formation are $ΔH^\circ_{f,298}[$HClO$_4$(g)$]=-0.6\pm$1 kcal/mol and $ΔH^\circ_{f,298}[$Cl$_2$O$_7$(g)$]=65.9\pm$2 kcal/mol, the largest source of uncertainty being our inability to account for post-CCSD(T) correlation effects. While G2 and G3 theory have fairly large errors, G3X theory reproduces both values to within 2 kcal/mol.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
