Ab Initio Approach to Femtosecond Stimulated Raman Spectroscopy: Investigating Vibrational Modes Probed in Excited-State Relaxation of Quaterthiophenes
Ab Initio Approach to Femtosecond Stimulated Raman Spectroscopy: Investigating Vibrational Modes Probed in Excited-State Relaxation of Quaterthiophenes
复制标题
飞秒受激拉曼光谱的从头算方法：研究四噻吩激发态弛豫中探测的振动模式
DOI：
10.1021/acs.jpca.0c06307
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Herbert, John M.
中科院分区：
文献类型：
--
作者：
Dasgupta, Saswata;Herbert, John M.
飞秒受激拉曼光谱（FSRS）是一种利用振动光谱研究激发态分子动力学的超快泵浦-探测技术。我们提出了一个第一性原理的FSRS的模拟协议，integratesab的initiomolecular动力学与计算共振拉曼光谱。理论计算可以监测特定振动模式随时间的演化，从而提供洞察的性质负责的实验FSRS信号的运动，我们应用这种技术来研究quaterthiophene衍生物。两种不同的quaterthiophene衍生物的S1状态通过同相和异相的伸缩模式，其频率耦合到二面角的骨干角，使光谱的演变反映了激发态弛豫向平面构象的松弛。模拟光谱有助于确认在现有的FSRS实验中探测的振动模式的实验分配四噻吩。
Femtosecond stimulated Raman spectroscopy (FSRS) is an ultrafast pump–probe technique designed to elucidate excited-state molecular dynamics by means of vibrational spectroscopy. We present a first-principles protocol for the simulation of FSRS that integratesab initiomolecular dynamics with computational resonance Raman spectroscopy. Theoretical calculations can monitor the time-dependent evolution of specific vibrational modes and thus provide insight into the nature of the motion responsible for the experimental FSRS signal, and we apply this technique to study quaterthiophene derivatives. The S1state of two different quaterthiophene derivatives relaxes via in-phase and out-of-phase stretching modes whose frequencies are coupled to the dihedral backbone angle, such that the spectral evolution reflects the excited-state relaxation toward a planar conformation. The simulated spectra aid in confirming the experimental assignment of the vibrational modes that are probed in the existing FSRS experiments on quaterthiophenes.