Junior research group Theoretical Chemistry

Dassia Egorova

Ultrafast Dynamics and Time-resolved Spectroscopy

Research

Methods

Modeling of ultrafast quantum dynamics


Wave function or density matrix? Ψ or ρ? Schrödinger or Liouville?

Coherent processes in complex systems require a reliable quantum dynamical description. The most powerful and accurate tool nowadays is the multi-configurational time-dependent Hartree approach (MCTDH). It is a direct wave function (Ψ) description that allows a numerically exact treatment of hundreds degrees of freedom. We are currently integrate this powerful method in our research. On the other hand, many ultrafast chemical processes can be described using a partitioning of the overall system into a relevant part (the 'system') and the remaining degrees of freedom (the 'bath'), and the resulting density-matrix (ρ) formalism. Up to know multi-level Redfield theory has been our working horse: in this method, a perturbative (up to the second order) treatment of the system-bath interaction allows for a computational efficiency and appears, if accurately implemented, to be a very reliable approximation for the description of ultrafast multilevel dissipative dynamics. It is very advantageous if only few degrees of freedom are strongly coupled and mainly determine the system dynamics.

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