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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >On the accuracy of computed excited-state dipole moments
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On the accuracy of computed excited-state dipole moments

机译：计算激发态偶极矩的精度

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The dipole moments of furan and pyrrole in many electronically excited singlet states have been determined using coupled cluster theory including large one-electron basis sets. The inclusion of connected triple excitations is shown to uniformly decrease the equation-of-motion coupled-cluster singles and doubles (EOM-CCSD) excitation energies by 0.04-0.24 eV, with an average reduction of 0.08 eV. Using a basis set larger than DZP(++)D (double-xi plus polarization augmented with atom- and molecule-centered diffuse functions) uniformly increases the computed EOM-CCSD excitation energies by 0.03-0.29 eV, with an average increase of 0.20 eV. The corresponding shifts in excited-state dipole moments are more erratic. Including connected triple excitations changes the computed dipole moments by an rms amount of 0.17 an. More importantly, using a larger basis set shifts the dipole moments by an rms amount of 0.52 au, with an increase or a decrease being equally likely. The CC dipole moments are compared to those from time-dependent density functional theory (TD-DFT) computed by Burcl, Amos, and Handy [Chem. Phys. Lett. 2002, 355, 8]. For 29 excited states of furan and pyrrole, the predicted TD-DFT dipole moments differ from the CC results by rms amounts of 1.6 au (HCTH functional) and 1.5 an (1397-1 functional). Including the asymptotic correction to TD-DFT developed by Tozer and Handy [J. Chem. Phys. 1998, 109, 10180; J. Comput. Chem. 1999, 20, 106] reduces the rms differences for both functionals to 1.2 an. If those Rydberg excited states with very large polarizabilities are excluded, the rms differences from the CC results for the remaining 17 excited states become 1.31 au (HCTH) and 0.88 an (1397-1). For asymptotically corrected functionals and this subset of states, the rms differences from the CC results are only 0.54 an (HCTHc) and 0.34 in (B97-1c). Thus, the Tozer-Handy asymptotic correction for TD-DFT significantly improves the predictions of excited-state dipole moments. For excited states without very large polarizabilities, good agreement is achieved between excited-state dipole moments computed by coupled cluster theory and by the asymptotically corrected B97-1c density. functional.
机译：已使用包括大的单电子基组的耦合簇理论确定了许多电子激发单重态中呋喃和吡咯的偶极矩。示出了包括所连接的三重激励，从而将运动方程耦合集群单双动（EOM-CCSD）激励能量均匀降低了0.04-0.24 eV，平均降低了0.08 eV。使用大于DZP（++）D（双xi加极化并以原子和分子为中心的扩散函数增强的极化）的基集，将计算出的EOM-CCSD激发能均匀增加0.03-0.29 eV，平均增加0.20 eV。激发态偶极矩的相应变化更加不稳定。包括连接的三重励磁，将计算出的偶极矩改变为有效值0.17 an。更重要的是，使用较大的基集会使偶极矩移动均方根值0.52 au，同样有可能增加或减少。将CC偶极矩与Burcl，Amos和Handy [Chem。物理来吧2002，355，8]。对于呋喃和吡咯的29个激发态，预测的TD-DFT偶极矩不同于CC结果，均方根值分别为1.6 au（HCTH功能）和1.5 an（1397-1功能）。包括由Tozer和Handy开发的TD-DFT的渐近校正[J．化学物理1998，109，10180; J.计算机化学[1999，20，106]将两种功能的均方根差减小到1.2 an。如果排除那些具有非常大极化率的里德堡激发态，则其余17个激发态与CC结果的均方根差变为1.31 au（HCTH）和0.88 an（1397-1）。对于渐近校正的功能和状态子集，与CC结果的均方根差仅为（HCTHc）0.54 an（B97-1c）和0.34。因此，针对TD-DFT的Tozer-Handy渐近校正大大改善了对激发态偶极矩的预测。对于没有很大极化率的激发态，通过耦合簇理论和渐近校正的B97-1c密度计算出的激发态偶极矩之间达成了良好的一致性。功能。

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