• 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 >Substituent effects on dynamics at conical intersections: Cycloheptatrienes
【24h】

Substituent effects on dynamics at conical intersections: Cycloheptatrienes

机译：圆锥形交叉口上的取代基对动力学的影响：环庚二烯

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

Using selective methyl substitution, we study the effects of vibrational dynamics at conical intersections in unsaturated hydrocarbons. Here, we investigate the excited state nonadiabatic dynamics of cycloheptatriene (CHT) and its relation to dynamics in other polyenes by comparing CHT with 7-methyl CHT, 7-ethyl CHT, and perdeuterated CHT using time-resolved photoelectron spectroscopy and photoelectron anisotropy. Our results suggest that, upon ππ-excitation to the bright 2A″ state, we observe an early intersection with the dark 2A′ state close to the Franck-Condon region with evidence of wavepacket bifurcation. This indicates that the wavepacket evolves on both states, likely along a planarization coordinate, with the majority of the flux undergoing nonadiabatic transition via conical intersections within 100 fs following light absorption. In CHT, large amplitude motion along the planarization coordinate improves the intra-ring π-overlap, yielding a delocalized electronic density. However, substitutions in 7 position, chosen to modify the inertia of the planarization motion, did not markedly alter the first step in the sequential kinetic scheme. This suggests that there is a crossing of potential energy surfaces before planarization is achieved and, thus, nonadiabatic transition likely takes place far away from a local minimum.
机译：使用选择性甲基取代，我们研究了不饱和烃在圆锥形交叉处的振动动力学影响。在这里，我们通过使用时间分辨光电子能谱和光电子各向异性比较CHT与7-甲基CHT，7-乙基CHT和全氘CHT，研究了环庚三烯（CHT）的激发态非绝热动力学及其与其他多烯动力学的关系。我们的结果表明，在对亮2A''状态进行ππ激发后，我们观察到了与弗朗克-康登区附近的暗2A'状态的早期相交，并证明了波包分叉。这表明，波包在两种状态下都可能沿平坦化坐标演化，并且大部分通量在吸收光后100 fs内通过圆锥形相交点经历非绝热过渡。在CHT中，沿平面化坐标的大幅度运动会改善环内π重叠，从而产生离域电子密度。但是，选择7个位置的替换来修改平面化运动的惯性并没有显着改变顺序动力学方案中的第一步。这表明在实现平面化之前势能表面存在交叉，因此非绝热跃迁可能发生在远离局部最小值的地方。

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