Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram, Kerala 695551, India.
J Phys Chem A. 2020 Dec 31;124(52):10989-10996. doi: 10.1021/acs.jpca.0c09454. Epub 2020 Dec 17.
The role of two skeletal (C═C and C═O stretch) and O-H vibrational motions in the internal conversion dynamics associated with the coupled S(ππ*, A') -S(nπ*, A″) potential energy surfaces of alizarin are investigated theoretically. Quantum wavepacket dynamics simulations reveal a nonadiabatic population transfer from the "bright" S(ππ*, A') to "dark" S(nπ*, A″) state on a time scale of 10 fs. A detailed analysis of computed structural parameters, energetics, and time-dependent observables suggest that these vibrations promote the nonadiabatic dynamics before initiating the proton transfer process. We also discuss how the simultaneous evolution of multidimensional dynamics involving several vibrational degrees of freedom would increase the complexity, while analyzing the spectral and kinetic data of time-resolved spectroscopy measurements.
理论研究了茜素的耦合 S(ππ*, A')-S(nπ*, A″)势能面相关的内转换动力学中两个骨架（C═C 和 C═O 伸缩）和 O-H 振动运动的作用。量子波包动力学模拟揭示了在 10 fs 的时间尺度上，从“亮”S(ππ*, A')到“暗”S(nπ*, A″)态的非绝热跃迁。对计算得到的结构参数、能量和时变可观测量的详细分析表明，这些振动在引发质子转移过程之前促进了非绝热动力学。我们还讨论了涉及多个振动自由度的多维动力学的同时演化如何增加复杂性，同时分析了时间分辨光谱测量的光谱和动力学数据。
