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Title: Dual surface plasmon resonances in Ni nanoparticles in silica

We report the observations of two broad absorption bands (at ∼3.5 and ∼6.0 eV) in the optical absorption (OA) spectra of Ni nanoparticles (NPs) in silica. For the calculations of the OA spectra, Maxwell-Garnett type effective medium theory has been used with NP radii in the range of 1 – 50 nm. The peak positions of both the OA bands have been found to shift towards higher energy (blue-shift) with decrease in NP radius. In addition, the OA spectra are found to more sensitive for smaller NPs as compare to larger NPs. These observations are argued as due to the confinement of the mean free path of free electrons in Ni NPs. Based on this, we conclude that the observed OA bands are due to the surface plasmon resonance (SPR) absorptions irrespective of the satisfaction of the criteria of the SPR conditions, thus resolving the unclear understanding of the appearance of two absorption bands in Ni NPs.
Authors:
 [1] ;  [2]
  1. Department of Physics, Banwarilal Bhalotia College, Asansol – 713303, West Bengal (India)
  2. Department of Physics, Sidho-Kanho-Birsha University, Purulia – 723101, West Bengal (India)
Publication Date:
OSTI Identifier:
22490225
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1665; Journal Issue: 1; Conference: 59. DAE solid state physics symposium 2014, Tamilnadu (India), 16-20 Dec 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION SPECTRA; ABSORPTION SPECTROSCOPY; COMPARATIVE EVALUATIONS; ELECTRONS; EV RANGE; MEAN FREE PATH; NANOPARTICLES; NICKEL; SILICA; SURFACES