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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Implicit Zero-Point Vibration Energy and Thermal Corrections in Rapid Estimation of Enthalpies of Formation from Hartree-Fock Total Energy and Partial Charges
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Implicit Zero-Point Vibration Energy and Thermal Corrections in Rapid Estimation of Enthalpies of Formation from Hartree-Fock Total Energy and Partial Charges

机译：快速估算Hartree-Fock总能量和部分电荷形成焓的隐式零点振动能量和热校正

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摘要

The rapid estimation of basis set error and correlation energy from partial charges (REBECEP) method is improved in a way that makes superfluous the explicit zero-point energy and thermal correction calculations. This saves considerable computational effect and increases the computational efficiency of the method. The new REBECZTEP (zero-point energy and thermal correction included) parameters provide an energy that can be used to calculate an enthalpy of formation using atomic enthalpies and energies without any further correction. An intermediate level where only the zero-point energy is included in the parameters, REBECZEP parameters, is also studied. The performance of the new parameter set that corrects the HF-SCF energy using atomic partial charges was studied for the 6-31G(d) and 6-311+G(2d,p) basis sets, for Mulliken, natural population, and stockholder charges. A total of 117 closed-shell neutral molecules with correctly measured experimental enthalpies of formation from the G2/97 and G3/99 database composed of H, C, N, O, and F atoms were selected for the test. The best REBECZTEP results were obtained using the HF/6-311+G(2d,p) natural population analysis charges. The average absolute deviation from the experimental enthalpies of formation for 115 molecules is 1.48 kcal/mol. This deviation was decreased to 1.22 kcal/mol on a reduced set of 110 molecules. This compares favorably to our previous best REBECEP results on the same test set of 117 molecules (average absolute deviation: 1.65 kcal/mol). These results also compare favorably to Gaussian-3 and B3LYP/6-311+G(3df,2p) ethalpies of formation (for 51 large molecules the corresponding average absolute deviations are 0.94 and 7.09 kcal/mol, respectively). The considerably faster REBECZTEP method performs considerably better for the 117 molecules with a moderate 6-31G(d) basis set than the B3LYP method with large 6-311+G(3d,2p) basis set.
机译：通过部分电荷快速估算基集误差和相关能量的方法（REBECEP），使多余的显式零点能量和热校正计算变得多余。这节省了可观的计算效果并提高了该方法的计算效率。新的REBECZTEP（包括零点能量和热校正）参数提供的能量可用于使用原子焓和能量来计算形成焓，而无需任何进一步校正。还研究了中间水平，其中仅零点能量包含在参数REBECZEP参数中。针对6-31G（d）和6-311 + G（2d，p）基集，穆里肯，自然人口和股票持有者，研究了使用原子偏电荷校正HF-SCF能量的新参数集的性能。收费。从由H，C，N，O和F原子组成的G2 / 97和G3 / 99数据库中，总共选择了117个具有正确测量的实验形成焓的闭壳中性分子进行测试。使用HF / 6-311 + G（2d，p）自然种群分析电荷可获得最佳的REBECZTEP结果。 115个分子与实验形成焓的平均绝对偏差为1.48 kcal / mol。在减少的一组110个分子上，该偏差降低到1.22 kcal / mol。这与我们先前在117个分子的同一测试集上获得的最佳REBECEP结果（平均绝对偏差：1.65 kcal / mol）相比具有优势。这些结果也比高斯3和B3LYP / 6-311 + G（3df，2p）的形成焓好（对于51个大分子，相应的平均绝对偏差分别为0.94和7.09 kcal / mol）。对于具有中等6-31G（d）基集的117个分子，快得多的REBECZTEP方法的性能要比具有较大6-311 + G（3d，2p）基集的B3LYP方法的性能好得多。

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