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Title: On the alternatives for bath correlators and spectral densities from mixed quantum-classical simulations

Journal Article · · Journal of Chemical Physics
DOI:https://doi.org/10.1063/1.4769079· OSTI ID:22099127
;  [1];  [2]
  1. Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States)
  2. Max Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, 01187 Dresden (Germany)

We investigate on the procedure of extracting a 'spectral density' from mixed QM/MM calculations and employing it in open quantum systems models. In particular, we study the connection between the energy gap correlation function extracted from ground state QM/MM and the bath spectral density used as input in open quantum system approaches. We introduce a simple model which can give intuition on when the ground state QM/MM propagation will give the correct energy gap. We also discuss the role of higher order correlators of the energy-gap fluctuations which can provide useful information on the bath. Further, various semiclassical corrections to the spectral density, are applied and investigated. Finally, we apply our considerations to the photosynthetic Fenna-Matthews-Olson complex. For this system, our results suggest the use of the Harmonic prefactor for the spectral density rather than the Standard one, which was employed in the simulations of the system carried out to date.

OSTI ID:
22099127
Journal Information:
Journal of Chemical Physics, Vol. 137, Issue 22; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
Country of Publication:
United States
Language:
English