Geometry of the transition state in the driven dynamics of molecular and spintronic systems

• Applicant: Professor Dr. Jörg Main
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 389136112

Transitions of systems between different states take place in many physical and chemical systems. The mechanism, how a reaction takes place, the reaction rate, and in particular possibilities to control the reaction are of high interest. Transition state theory (TST)allows to describe activated reactions qualitatively as well as quantitatively. A field of growing interest over the recent years are time-dependent systems which are externally driven by noise and/or external fields, because they allow one to actively control the reaction rates and pathways. Time-dependent extensions of TST are capable of exactly describing such driven systems, however, so far, the developed methods are restricted to simple, one-dimensional model systems. The aim of the project is the development of methods which can be applied to realistic systems with finite reactant basins and many degrees of freedom, and, in particular, allow to exactly describe the reaction dynamics of time-dependent, driven, and high-dimensional activated systems. For this purpose, it is the first goal to define and construct an appropriate, time-dependent and high-dimensional dividing surface which uniquely separates reactants and products at all times. A second goal is the application of the developed methods to the fields of chemistry and physics with examples including, e.g., the LiCN isomerization reaction and spin-torque-switching in ferromagnets. For these systems we want to describe globally and exactly the time-dependent reaction dynamics, determine the respective reaction rates, and control the reaction pathways by applying an appropriate external driving.

• DFG Programme: Research Grants