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Title: Dissipation enhanced vibrational sensing in an olfactory molecular switch

Motivated by a proposed olfactory mechanism based on a vibrationally activated molecular switch, we study electron transport within a donor-acceptor pair that is coupled to a vibrational mode and embedded in a surrounding environment. We derive a polaron master equation with which we study the dynamics of both the electronic and vibrational degrees of freedom beyond previously employed semiclassical (Marcus-Jortner) rate analyses. We show (i) that in the absence of explicit dissipation of the vibrational mode, the semiclassical approach is generally unable to capture the dynamics predicted by our master equation due to both its assumption of one-way (exponential) electron transfer from donor to acceptor and its neglect of the spectral details of the environment; (ii) that by additionally allowing strong dissipation to act on the odorant vibrational mode, we can recover exponential electron transfer, though typically at a rate that differs from that given by the Marcus-Jortner expression; (iii) that the ability of the molecular switch to discriminate between the presence and absence of the odorant, and its sensitivity to the odorant vibrational frequency, is enhanced significantly in this strong dissipation regime, when compared to the case without mode dissipation; and (iv) that details of the environment absent frommore » previous Marcus-Jortner analyses can also dramatically alter the sensitivity of the molecular switch, in particular, allowing its frequency resolution to be improved. Our results thus demonstrate the constructive role dissipation can play in facilitating sensitive and selective operation in molecular switch devices, as well as the inadequacy of semiclassical rate equations in analysing such behaviour over a wide range of parameters.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [4]
  1. Centre for Quantum Technologies, National University of Singapore, Singapore 117543 (Singapore)
  2. Atomic and Laser Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)
  3. Photon Science Institute and School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom)
  4. (United Kingdom)
Publication Date:
OSTI Identifier:
22415853
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 74 ATOMIC AND MOLECULAR PHYSICS; CAPTURE; COMPARATIVE EVALUATIONS; DEGREES OF FREEDOM; ELECTRON TRANSFER; ELECTRONIC STRUCTURE; ELECTRONS; OPERATION; POLARONS; RESOLUTION; SEMICLASSICAL APPROXIMATION; SENSITIVITY; SWITCHES; VIBRATIONAL STATES