Mixed Quantum/Classical Method for Nonadiabatic Quantum Dynamics in Explicit Solvent Models: The ππ */nπ* Decay of Thymine in Water as a Test Case

Na Cerezo (1) , Na Liu (2) , Na Lin (3) , Xian Zhao (3) , Roberto Improta (4, 5) , Fabrizio Santoro (6)

1 Departamento de Química Física, Facultad de Química
2 School of Physics and Optoelectronics Engineering
3 State Key Laboratory of Crystal Materials
4 DICO - Dynamique et Interactions en phase Condensée
5 CNR – Istituto di Biostrutture e Bioimmagini
6 ICCOM - Istituto di Chimica dei Composti Organometallici

We present a novel mixed quantum classical dynamical method to include solvent effects on internal conversion (IC) processes. All the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics, while the motion of an explicit solvent model is described by an ensemble of classical trajectories. The mutual coupling of the solute and solvent dynamics is included within a mean-field framework and the quantum and classical equations of motions are solved simultaneously. As a test case we apply our method to the ultrafast ππ* → nπ* decay of thymine in water. Solvent dynamical response modifies IC yield already on the 50 fs time scale. This effect is due to water librational motions that stabilize the most populated state. Pure static disorder, that is, the existence of different solvent configurations when photoexcitation takes place, also has a remarkable impact on the dynamics.

Domains: Theoretical and/or physical chemistry; Chemical Physics [physics.chem-ph]

Na Cerezo, Na Liu, Na Lin, Xian Zhao, Roberto Improta, et al.. Mixed Quantum/Classical Method for Nonadiabatic Quantum Dynamics in Explicit Solvent Models: The ππ */nπ* Decay of Thymine in Water as a Test Case. Journal of Chemical Theory and Computation, 2018, 14 (2), pp.820 - 832. ⟨10.1021/acs.jctc.7b01015⟩. ⟨cea-01741540⟩