Ultrafast decay dynamics of electronically excited 2-ethylpyrrole.
Ultrafast decay dynamics of electronically excited 2-ethylpyrrole.
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DOI：
10.1039/d1cp01090e
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发表时间：
2021-08
期刊：
影响因子：
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通讯作者：
Wenpeng Yuan;Dongyuan Yang;Baihui Feng;Yanjun Min;Zhichao Chen;Shengrui Yu;Guorong Wu;Xueming Yang
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文献类型：
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作者：
Wenpeng Yuan;Dongyuan Yang;Baihui Feng;Yanjun Min;Zhichao Chen;Shengrui Yu;Guorong Wu;Xueming Yang
利用飞秒时间分辨光电子成像方法研究了2-乙基吡咯在254.8-218.0 nm紫外光激发下的激发态衰减动力学。仔细分析了在所有泵浦波长下的时间分辨光电子谱和光电子角分布，得出如下结果：在最长泵浦波长（254.8，248.3，246.1nm）下，2-乙基吡咯被激发到S1（1πσ*）态，寿命约为50 fs。在248.3，246.1和237.4nm处，激发出另一个具有里德伯特征的激发态。在237.4nm处，该态的寿命为1570 fs，在另外两个泵浦波长处，寿命稍长。在最短的泵浦波长（230.8和218.0 nm）下，2-乙基吡咯被激发到暂时归属于11ππ* 态的状态，对于较长和较短的泵浦波长分别具有75 ± 15和48 ± 10 fs的寿命。内转换到S1（1πσ*）态可能是11ππ* 态的衰变机制之一。
The excited-state decay dynamics of 2-ethylpyrrole following UV excitation in the wavelength range of 254.8-218.0 nm is investigated in detail using the femtosecond time-resolved photoelectron imaging method. The time-resolved photoelectron spectra and photoelectron angular distributions at all pump wavelengths are carefully analysed and the following picture is derived: at the longest pump wavelengths (254.8, 248.3 and 246.1 nm), 2-ethylpyrrole is excited to the S1(1πσ*) state having a lifetime of about 50 fs. At 248.3, 246.1 and 237.4 nm, another excited state of Rydberg character is excited. The lifetime of this state is ∼570 fs at 237.4 nm and becomes slightly longer at other two pump wavelengths. At the shortest pump wavelengths (230.8 and 218.0 nm), 2-ethylpyrrole is excited to a state which is tentatively assigned to the 11ππ* state, having a lifetime of 75 ± 15 and 48 ± 10 fs for the longer and shorter pump wavelengths, respectively. Internal conversion to the S1(1πσ*) state might be one of the decay mechanisms of the 11ππ* state.