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Title: Linewidths and line shapes in the vicinity of graphene

It is well known that graphene, by virtue of its pi-cloud delocalization, has a continuum of electronic energy states and thus behaves nearly like a metal. Instances involving quenching of electronic energy excitation in fluorophores placed in the proximity of graphene sheets are well documented. In this paper, we perform theoretical investigations on the broadening of vibrational and electronic transitions in the vicinity of graphene. We find that for CO vibrations in the vicinity of undoped graphene, the broadening at a distance of 5 Å is ∼0.008 cm{sup −1}(κ{sup ~}=2, κ{sup ~} being the effective dielectric constant). In comparison, for electronic transitions, the linewidth is much larger, being of the order of several cm{sup −1}. Also, if the transition dipole were parallel to the graphene sheet, the linewidth would be reduced to half the value for the case where it is perpendicular, an observation which should be easy to check experimentally for electronic transitions. This should be observable for the f − f transitions (which are rather narrow) of Lanthanide complexes placed within a distance of a few nanometers from a graphene sheet. Further the linewidth would have a (distance){sup −4} dependence as one varies the distance from graphene.
Authors:
;  [1]
  1. Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012 (India)
Publication Date:
OSTI Identifier:
22419838
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 8; Other Information: (c) 2014 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; CARBON MONOXIDE; COMPARATIVE EVALUATIONS; DIPOLES; DISTANCE; EXCITATION; GRAPHENE; METALS; PERMITTIVITY; QUENCHING; RARE EARTH COMPLEXES