Following the relaxation dynamics of photoexcited aniline in the 273-266 nm region using time-resolved photoelectron imaging.
Following the relaxation dynamics of photoexcited aniline in the 273-266 nm region using time-resolved photoelectron imaging.
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DOI：
10.1063/1.4813005
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发表时间：
2013-07
期刊：
影响因子：
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通讯作者：
James O. F. Thompson;Ruth A. Livingstone;D. Townsend
中科院分区：
文献类型：
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作者：
James O. F. Thompson;Ruth A. Livingstone;D. Townsend
利用时间分辨光电子成像技术研究了273-266 nm紫外光照射下苯胺在气相中的电子激发弛豫动力学。我们发现，在所有研究的波长，激发主要是长寿命（>1 ns）的S1（ππ（*））状态，它表现出超快的分子内振动重分布在<1 ps的时间尺度。在以苯胺吸收光谱中的共振跃迁为中心的激发波长处，我们也看到了这种状态在动力学中发挥作用的明确证据，这些共振跃迁先前已被分配给较高的S2（3s scin πσ（*））状态。然而，在所研究的激发波长范围内，我们没有看到S1（ππ（*））和S2（3s scin πσ（*））态之间的任何非绝热耦合的迹象。
Time-resolved photoelectron imaging was used to investigate the relaxation dynamics of electronically excited aniline in the gas-phase following ultraviolet irradiation in the 273-266 nm region. We find that at all wavelengths studied, excitation is predominantly to the long-lived (>1 ns) S1(ππ(*)) state, which exhibits ultrafast intramolecular vibrational redistribution on a <1 ps timescale. At excitation wavelengths centred on resonant transitions in the aniline absorption spectrum that have previously been assigned to the higher lying S2(3s∕πσ(*)) state, we also see clear evidence of this state playing a role in the dynamics. However, we see no indication of any non-adiabatic coupling between the S1(ππ(*)) and S2(3s∕πσ(*)) states over the range of excitation wavelengths studied.