...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >The Vibronic Structure of Electronic Absorption Spectra of Large Molecules:A Time-Dependent Density Functional Study on the Influence of'Exact'Hartree-Fock Exchange
【24h】

The Vibronic Structure of Electronic Absorption Spectra of Large Molecules:A Time-Dependent Density Functional Study on the Influence of'Exact'Hartree-Fock Exchange

机译：大分子电子吸收光谱的振动子结构：“精确” Hartree-Fock交换影响的时变密度泛函研究

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The functional dependence of excited-state geometries and normal modes calculated with time-dependent density functional theory(TDDFT)is investigated on the basis of vibronic structure calculations of the absorption spectra of large molecules.For a set of molecules covering a wide range of different structures including organic dyes,biological chromophores,and molecules of importance in material science,quantum mechanical simulations of the vibronic structure are performed.In total over 40 singlet-singlet transitions of neutral closed-shell compounds and doublet-doublet transitions of neutral radicals,radical cations,and anions are considered.Calculations with different standard density functionals show that the predicted vibronic structure critically depends on the fraction of the"exact"Hartree-Fock exchange(EEX)included in hybrid functionals.The effect can been traced back to a large influence of EEX on the geometrical displacement upon excitation.On the contrary,the dependence of the results on the choice of the local exchange-correlation functional is found to be rather small.On the basis of detailed comparisons with experimental spectra conclusions are drawn concerning the optimum amount of EEX mixing for a proper description of the excited-state properties.The relationship of the quality of the simulated spectra with the errors for 0-0 transition energies is discussed.For the investigated singlet-singlet pi->pi~* transitions and the first strongly dipole-allowed transitions of PAH radical cations some rules of thumb concerning the optimum portion of EEX are derived.However,in general no universal amount of EEX seems to exist that gives a uniformly good description for all systems and states.Nevertheless an inclusion of about 30-40%of EEX in the functional is found empirically to yield in most cases simulated spectra that compare very well with those from experiment and thus seems to be necessary for an accurate description of the excited-state geometry.Pure density functionals that are computationally more efficient provide less accurate spectra in most cases and their application is recommended solely for comparison purposes to obtain estimates for the reliability of the theoretical predictions.
机译：在大分子吸收光谱的振动电子结构计算的基础上，研究了基于时变密度泛函理论（TDDFT）计算的激发态几何形状和正态模的函数依赖关系。进行了包括有机染料，生物发色团和材料科学中重要分子的结构的振动电子结构的量子力学模拟。总共进行了40多个中性闭壳化合物的单重态-单重跃迁和中性自由基，自由基的双重态-双重跃迁。具有不同标准密度泛函的计算表明，预测的振动子结构关键取决于杂化泛函中包含的“精确” Hartree-Fock交换（EEX）的分数。该效应可以追溯到较大的EEX对激发时几何位移的影响。相反，th的依赖性在局部交换相关函数的选择上发现的结果很小。在与实验光谱进行详细比较的基础上，得出了有关EEX混合量的最佳描述以正确描述激发态性质的结论。讨论了模拟光谱质量与0-0跃迁能误差之间的关系。对于研究的单重态pi-> pi〜*跃迁和PAH自由基阳离子的第一个强偶极子跃迁，一些经验法则然而，总的来说，似乎没有通用数量的EEX可以对所有系统和状态给出统一的良好描述。然而，根据经验发现，在功能中包含约30-40％的EEX在大多数情况下，可以产生模拟光谱，该光谱与实验光谱非常吻合，因此似乎对于准确描述激发态几何是必要的。计算效率更高的nsity函数在大多数情况下提供的光谱较不准确，建议仅将它们的应用用于比较目的，以获得对理论预测可靠性的估计。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号