PMID- 33218227
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20201123
IS  - 1089-7690 (Electronic)
IS  - 0021-9606 (Linking)
VI  - 153
IP  - 19
DP  - 2020 Nov 21
TI  - Exciton transfer using rates extracted from the "hierarchical equations of 
      motion".
PG  - 194112
LID - 10.1063/5.0027373 [doi]
AB  - Frenkel exciton population dynamics of an excitonic dimer is studied by comparing 
      the results from a quantum master equation involving rates from second-order 
      perturbative treatment with respect to the excitonic coupling with the 
      non-perturbative results from "Hierarchical Equations of Motion" (HEOM). By 
      formulating generic Liouville-space expressions for the rates, we can choose to 
      evaluate them either via HEOM propagations or by applying the cumulant expansion. 
      The coupling of electronic transitions to bath modes is modeled either as 
      overdamped oscillators for the description of thermal bath components or as 
      underdamped oscillators to account for intramolecular vibrations. Cases of 
      initial nonequilibrium and equilibrium vibrations are discussed. In the case of 
      HEOM, initial equilibration enters via a polaron transformation. Pointing out the 
      differences between the nonequilibrium and equilibrium approach in the context of 
      the projection operator formalism, we identify a further description, where the 
      transfer dynamics is driven only by fluctuations without involvement of 
      dissipation. Despite this approximation, this approach can also yield meaningful 
      results in certain parameter regimes. While for the chosen model, HEOM has no 
      technical advantage for evaluation of the rate expressions compared to cumulant 
      expansion, there are situations where only evaluation with HEOM is applicable. 
      For instance, a separation of reference and interaction Hamiltonian via a polaron 
      transformation to account for the interplay between Coulomb coupling and 
      vibrational oscillations of the bath at the level of a second-order treatment can 
      be adjusted for a treatment with HEOM.
FAU - Seibt, Joachim
AU  - Seibt J
AUID- ORCID: 0000000151628883
AD  - Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18059 
      Rostock, Germany.
FAU - Kuhn, Oliver
AU  - Kuhn O
AUID- ORCID: 0000000251322961
AD  - Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18059 
      Rostock, Germany.
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Chem Phys
JT  - The Journal of chemical physics
JID - 0375360
SB  - IM
EDAT- 2020/11/22 06:00
MHDA- 2020/11/22 06:01
CRDT- 2020/11/21 05:21
PHST- 2020/11/21 05:21 [entrez]
PHST- 2020/11/22 06:00 [pubmed]
PHST- 2020/11/22 06:01 [medline]
AID - 10.1063/5.0027373 [doi]
PST - ppublish
SO  - J Chem Phys. 2020 Nov 21;153(19):194112. doi: 10.1063/5.0027373.