Influence of Coherent Tunneling and Incoherent Hopping on the Charge Transfer Mechanism in Linear Donor-Bridge-Acceptor Systems

Guangqi Li, Niranjan Govind, Mark A Ratner, Christopher J. Cramer, Laura Gagliardi

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

The mechanism of charge transfer has been observed to change from tunneling to hopping with increasing numbers of DNA base pairs in polynucleotides and with the length of molecular wires. The aim of this paper is to investigate this transition by examining the population dynamics using a tight-binding Hamiltonian with model parameters to describe a linear donor-bridge-acceptor (D-B-A) system. The model includes a primary vibration and an electron-vibration coupling at each site. A further coupling of the primary vibration with a secondary phonon bath allows the system to dissipate energy to the environment and reach a steady state. We apply the quantum master equation (QME) approach, based on second-order perturbation theory in a quantum dissipative system, to examine the dynamical processes involved in charge-transfer and follow the population transfer rate at the acceptor, ka, to shed light on the transition from tunneling to hopping. With a small tunneling parameter, V, the on-site population tends to localize and form polarons, and the hopping mechanism dominates the transfer process. With increasing V, the population tends to be delocalized and the tunneling mechanism dominates. The competition between incoherent hopping and coherent tunneling governs the mechanism of charge transfer. By varying V and the total number of sites, we also examine the onset of the transition from tunneling to hopping with increasing length.

Original languageEnglish
Pages (from-to)4889-4897
Number of pages9
JournalJournal of Physical Chemistry Letters
Volume6
Issue number24
DOIs
Publication statusPublished - Dec 17 2015

Fingerprint

Charge transfer
charge transfer
Hamiltonians
Polarons
Polynucleotides
Population dynamics
vibration
DNA
Wire
polynucleotides
Electrons
polarons
baths
deoxyribonucleic acid
perturbation theory
wire
electrons
energy

Keywords

  • coherent tunneling
  • donor-bridge-acceptor
  • incoherent hopping
  • quantum master equation

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Influence of Coherent Tunneling and Incoherent Hopping on the Charge Transfer Mechanism in Linear Donor-Bridge-Acceptor Systems. / Li, Guangqi; Govind, Niranjan; Ratner, Mark A; Cramer, Christopher J.; Gagliardi, Laura.

In: Journal of Physical Chemistry Letters, Vol. 6, No. 24, 17.12.2015, p. 4889-4897.

Research output: Contribution to journalArticle

Li, Guangqi ; Govind, Niranjan ; Ratner, Mark A ; Cramer, Christopher J. ; Gagliardi, Laura. / Influence of Coherent Tunneling and Incoherent Hopping on the Charge Transfer Mechanism in Linear Donor-Bridge-Acceptor Systems. In: Journal of Physical Chemistry Letters. 2015 ; Vol. 6, No. 24. pp. 4889-4897.
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