School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram 695551, India.
J Chem Phys. 2021 Sep 7;155(9):094301. doi: 10.1063/5.0060934.
We employ the ab initio molecular dynamics within the surface hopping method to explore the excited-state intramolecular proton transfer taking place on the coupled "bright" S (ππ*) and "dark" S (nπ*) states of 3-hydroxychromone. The nonadiabatic population transfer between these states via an accessible conical intersection would open up multiple proton transfer pathways. Our findings reveal the keto tautomer formation via S on a timescale similar to the O-H in-plane vibrational period (<100 fs). Structural analysis indicates that a few parameters of the five-membered proton transfer geometry that constitute the donor (hydroxyl) and acceptor (carbonyl) groups would be adequate to drive the enol to keto transformation. We also investigate the role of O-H in-plane and out-of-plane vibrational motions in the excited-state dynamics of 3-hydroxychromone.
我们采用表面跳跃法中的从头算分子动力学来探索 3-羟基色酮上耦合的“亮” S（ππ*）和“暗” S（nπ*）态之间发生的激发态分子内质子转移。通过可及的锥形交叉点，这些态之间的非绝热种群转移将开辟多条质子转移途径。我们的研究结果表明，酮式互变异构体的形成通过 S 进行，时间尺度与 O-H 面内振动周期相似（<100 fs）。结构分析表明，构成供体（羟基）和受体（羰基）基团的五元质子转移几何形状的几个参数足以驱动烯醇到酮的转变。我们还研究了 O-H 面内和面外振动运动在 3-羟基色酮的激发态动力学中的作用。
