Long-range corrected density functional calculations of chemical reactions: redetermination of parameter.
Long-range corrected density functional calculations of chemical reactions: redetermination of parameter.
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DOI：
10.1063/1.2721532
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发表时间：
2007-04
期刊：
影响因子：
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通讯作者：
Jong-Won Song;Tsuyoshi Hirosawa;T. Tsuneda;K. Hirao
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文献类型：
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作者：
Jong-Won Song;Tsuyoshi Hirosawa;T. Tsuneda;K. Hirao
采用远程校正（LC）方案进行化学反应计算，改进了密度泛函理论（DFT）中的远程交换效应[J]。化学。物理学报（英文版）；[j].科学通报，2004(5)。通过对计算得到的雾化能的误差百分比进行均方根拟合，对LC方案参数mu进行了新的确定。因此，优化后的参数mu为0.47，高于之前的参数mu=0.33。利用这一新参数mu，首次将LC-DFT应用于G2基准集分子的几何优化。因此，与之前的LC-DFT和混合B3LYP结果相比，这种新的LC-DFT给出了更准确的键长和键角。根据这一结果，作者计算了常规DFT计算中低估的基准反应集的反应势垒高度能。计算结果表明，LC-DFT提供了更精确的势垒高度能，误差小于以往LC-DFT和B3LYP研究的一半。为了检验新LC-DFT的一般有效性，作者最后计算了反应焓。结果，他们发现使用新mu的LC方案明显提高了计算焓的准确性。因此，作者得出结论，在DFT计算中，远程交换效应的不充分包含是对反应势垒的低估的原因，并且使用新参数的LC-DFT是理论上研究化学反应的有力工具。
Chemical reaction calculations were carried out using the long-range correction (LC) scheme, which improves long-range exchange effects in density functional theory (DFT) [J. Chem. Phys. 115, 3540 (2001); 120, 8425 (2004)]. A new determination of the LC scheme parameter mu was made by a root mean square fit of the percent error in calculated atomization energies. As a result, the parameter mu was optimized as 0.47, which is higher than the previous one (mu=0.33). Using this new parameter mu, LC-DFT was firstly applied to geometry optimizations of the G2 benchmark set molecules. Consequently, this new LC-DFT gave more accurate bond lengths and bond angles than previous LC-DFT and hybrid B3LYP results. Following this result, the authors calculated reaction barrier height energies of benchmark reaction sets, which have been underestimated in conventional DFT calculations. Calculated results showed that LC-DFT provided much more accurate barrier height energies with errors less than half those of previous LC-DFT and B3LYP studies. To test the general validity of the new LC-DFT, the authors finally calculated reaction enthalpies. As a result, they found that the LC scheme using the new mu clearly improved the accuracy of calculated enthalpies. The authors therefore conclude that the insufficient inclusion of long-range exchange effects is responsible for the underestimation of reaction barriers in DFT calculations and that LC-DFT using the new parameter is a powerful tool for theoretically investigating chemical reactions.