• 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 >Conformational Effects on the Ultraviolet Absorption Spectrum of n-Tetrasilane: Multistate Complete Active Space Second-Order Perturbation Theory Treatment
【24h】

Conformational Effects on the Ultraviolet Absorption Spectrum of n-Tetrasilane: Multistate Complete Active Space Second-Order Perturbation Theory Treatment

机译：正构硅烷的紫外吸收光谱的构象效应：多状态完全活性空间二阶摄动理论处理

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

A theoretical analysis and interpretation of the reported UV absorption spectra of the anti and gauche conformers of n-tetrasilane is offered, based on the results of multistate complete active space second-order perturbation theory (MS-CASPT2) calculations for their low-energy valence electronic excited states. A generally contracted basis set of atomic natural orbitals (ANOs) and a ground-state geometry optimized at the second-order Moller-Plesset perturbation theory (MP2) level by use of Dunning's correlation-consistent triple-ζ basis set (cc-pVTZ) have been used. Six valence excited states are calculated for the anti conformer. In terms of natural orbitals they correspond to single-electron promotions from the σ_1 highest occupied molecular orbital (HOMO) to four σ~* and two π~* valence orbitals. Eight valence excited states are compared for the gauche conformer. Six of these correlate with the states calculated for the anti conformer, while two are new and correspond to single-electron promotions from the σ_2 HOMO-1 to the σ_1~* and σ_2~* valuence orbitals. The interpretation of the UV absorption spectrum of n-tetrasilane in terms of the present calculations show strong contributions from six valence states instead of four. The main contribution to the second band is from the gauche conformer and involves an excitation from the σ_2 HOMO-1 orbital, which was previously not emphasized. The description of the conformational effects on the spectrum confirms the proposal that the energy of the electronic transitions has a weak dependence on the backbone dihedral angle, while the computed intensity is strongly affected by the conformation.
机译：基于多态完整活性空间二阶微扰理论（MS-CASPT2）计算低能价的结果，对正丁硅烷的反构和构团构象构象的紫外吸收光谱进行了理论分析和解释。电子激发态。通过使用Dunning的相关一致三重ζ基本集（cc-pVTZ），在二阶Moller-Plesset摄动理论（MP2）级别优化的原子自然轨道（ANO）的一般收缩基集和基态几何被用过。计算反构象体的六价激发态。就自然轨道而言，它们对应于从σ_1最高占据分子轨道（HOMO）到四个σ〜*和两个π〜*价原子轨道的单电子促进。比较了gauche构象体的八价激发态。其中六个与为反构象异构体计算的状态相关，而两个为新状态，对应于从σ_2HOMO-1到σ_1〜*和σ_2〜*值轨道的单电子提升。根据目前的计算，对正甲硅烷的紫外线吸收光谱的解释显示出六个价态而不是四个价态的重要贡献。对第二个波段的主要贡献来自于gauche构象仪，并且涉及到以前从未强调过的σ_2HOMO-1轨道的激发。对光谱上的构象效应的描述证实了这样的建议，即电子跃迁的能量对主链二面角的依赖性较弱，而计算强度受到构象的强烈影响。

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