Freiburg 2024 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

MO: Fachverband Molekülphysik

MO 20: Theoretical Molecular Physics

MO 20.5: Talk

Thursday, March 14, 2024, 15:30–15:45, HS 3042

Multi-state mapping approach to surface hopping — •Johan Runeson and David Manolopoulos — Physical and Theoretical Chemistry Laboratory, University of Oxford, UK

Many important problems in physics and chemistry involve non-adiabatic dynamics: nuclear motion on two or more coupled electronic potential energy surfaces. The most popular method to treat this problem is fewest-switches surface hopping (FSSH), which involves stochastic hops of classical nuclear trajectories between adiabatic electronic states. This method can be used with ab initio potentials and is widely applied in photochemistry. However, its long-standing problems are overcoherence and violation of detailed balance. A new ‘mapping approach to surface hopping’ (MASH) [1] appears to resolve many of these issues: it avoids ad hoc decoherence corrections and provably relaxes to the correct quantum–classical equilibrium. Although originally developed for two states, we have extended the method to any number of states and applied it to a variety of problems, including gas-phase photochemistry, spin-boson models, and exciton transfer in photosynthetic systems [2]. In all cases, we find MASH to be more accurate as well as more numerically tractable than FSSH. The talk will summarize this development and mention some current exciting applications, including charge transport in organic materials.

[1] J. R. Mannouch and J. O. Richardson, J. Chem. Phys. 158, 104111 (2023). [2] J. E. Runeson and D. E. Manolopoulos. J. Chem. Phys. 159, 094115 (2023).

Keywords: Non-adiabatic; Surface hopping; Quantum-classical; Photosynthesis; Excitation energy transfer