Excitation wavelength dependent S1-state decay dynamics of 2-aminopyridine and 3-aminopyridine.
Excitation wavelength dependent S1-state decay dynamics of 2-aminopyridine and 3-aminopyridine.
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DOI：
10.1039/d3cp01487h
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发表时间：
2023-06
期刊：
影响因子：
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通讯作者：
Baihui Feng;Dongyuan Yang;Yanjun Min;Qinghua Gao;Benjie Fang;Guorong Wu;Xueming Yang
中科院分区：
文献类型：
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作者：
Baihui Feng;Dongyuan Yang;Yanjun Min;Qinghua Gao;Benjie Fang;Guorong Wu;Xueming Yang
利用飞秒时间分辨光电子成像技术研究了2-氨基吡啶和3-氨基吡啶激发到S1态的衰变动力学。两种分子的S1态寿命都随着振动能的增加而迅速减小。结果表明，除了系统间穿越到较低的三重态的T1，通过内部转换通过锥形交叉衰变到基态（S 0）起着越来越重要的作用，并成为占主导地位的振动状态远远高于S1状态的起源。2-氨基吡啶和3-氨基吡啶之间的比较表明，分子内氢键之间的NH 2基团的氢原子和杂环氮原子在2-氨基吡啶有效地阻碍了环变形在较低的振动状态，这是所需的波包到达S1/S 0的圆锥相交，因此减慢了S1到S 0的内部转换。
The decay dynamics of 2-aminopyridine and 3-aminopyridine excited to the S1 state is investigated using femtosecond time-resolved photoelectron imaging. The lifetime of the S1 state for both molecules shows a rapid decrease with the increase of the vibrational energy. It is shown that, besides intersystem crossing to the lower-lying triplet state of T1, the decay to the ground state (S0) via internal conversion through a conical intersection plays an increasingly important role and becomes dominant for vibrational states well above the S1 state origin. The comparison between 2-aminopyridine and 3-aminopyridine suggests that the intramolecular hydrogen bonding between a hydrogen atom of the NH2 group and the heterocyclic nitrogen atom in 2-aminopyridine effectively hinders the ring deformation at lower vibrational states which is required for the wavepacket to reach the S1/S0 conical intersection, and therefore slows down the S1 to S0 internal conversion.