Free energy methods

People

Project coordinator: Sergei Ivanov
Co-worker: Nicolas Künzel

Project description

Identifying reaction mechanisms and simulating reaction rates remains a challenge for molecular physics, as one has to face the full complexity of large molecular systems on timescales that by far exceed those accessible by regular MD. In other words, reactions are rare events and many ways to accelerate them exist. We opted to work with Metadynamics and methods based on Jarzynski equality. The former belongs to a broad class of 'penalty' methods, where a history-dependent biasing force hinders revisiting the regions of phase space during simulation. The negative of this very penalty potential constitutes the desired free energy profile. The latter is based on calculating the free energy barriers from non-equilibrium simulations. Once the free energy barrier is obtained the rate can be estimated by means of transition state theory

Publications

  1. S. D. Ivanov, I. Grant, D. Marx
    Journal of Chemical Physics 143, 124304 (2015)[LINK]
    Quantum free energy landscapes from ab initio path integral metadynamics: Double proton transfer in the formic acid dimer is concerted but not correlated
  2. Chris Rehhagen (Bachelor Thesis, 2014)
    Determining the free energies and reaction mechanisms via accelerated molecular dynamics