Fast degenerate correlation-corrected vibrational self-consistent field calculations of the vibrational spectrum of 4-mercaptopyridine.
Fast degenerate correlation-corrected vibrational self-consistent field calculations of the vibrational spectrum of 4-mercaptopyridine.
复制标题
4-巯基吡啶振动谱的快速简并相关校正振动自洽场计算。
DOI：
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发表时间：
2009
影响因子：
4.4
通讯作者：
D. Benoit
中科院分区：
文献类型：
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作者：
Inga Respondek;D. Benoit
我们引入了一种快速简并校正振动二阶 Møller-Plesset (fast-DCVMP2) 方法来计算大分子的非谐振动谱，其中全势能面的计算成本很高。我们检查了非自洽 Harris 函数作为稳健的预筛选技术的适用性，以取代我们之前研究中使用的半经验 PM3 模型。我们统计分析了模式-模式耦合强度，并提出了一种方案，可以更灵活地确定用于识别强耦合的阈值。我们的方法在甲醇分子上得到验证，并应用于巯基甲烷和吡啶，我们将结果与实验频率进行比较。我们表明，即使对于简并预计不会发挥重要作用的系统，振动自洽场能的标准微扰校正也会导致不可靠的结果。我们的快速技术得出的结果与标准 DCVMP2 计算获得的结果接近，但节省了大量时间。使用这项新技术，我们计算了 4-巯基吡啶（一种分子电子应用中有趣的化合物）的振动频率，并将我们的结果与实验值进行了比较。
We introduce a fast degeneracy-corrected vibrational second-order Møller-Plesset (fast-DCVMP2) method to compute anharmonic vibrational spectra of large molecules where the computational cost of the full potential energy surface is high. We examine the suitability of the non-self-consistent Harris functional as a robust prescreening technique to replace the semiempirical PM3 model used in our previous studies. We analyze the mode-mode coupling strength statistically and present a scheme that provides a more flexible determination of the threshold used to identify strong couplings. Our methodology is validated on the methanol molecule and applied to mercaptomethane and pyridine, where we compare our results with experimental frequencies. We show that a standard perturbative correction of the vibrational self-consistent field energy can lead to unreliable results even for systems where degeneracies are not expected to play an important role. Our fast technique leads to results close to those obtained with standard DCVMP2 calculations, but with substantial time savings. Using this new technique, we compute the vibrational frequencies of 4-mercaptopyridine, an interesting compound for molecular-electronic applications, and compare our results with experimental values.