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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/2520

Title: Temperature dependence of intrinsic infrared absorption in natural and chemical-vapor deposited diamond
Authors: Piccirillo, C
Davies, G
Mainwood, A.
Scarle, S
Penchina, CM
Mollart, T. P.
Lewis, KL
REMES, Zdenek
Pickles, CSJ
Issue Date: 2002
Citation: JOURNAL OF APPLIED PHYSICS, 92(2). p. 756-763
Abstract: Empirical rules are derived that describe the temperature dependence of the infrared absorption spectra of pure diamond for photons of energy hnu=500-4000 cm(-1). We show that with increasing temperature in the range 14<T<850 K, all the features in the infrared spectrum shift to lower frequency at very similar fractional rates. The rate for all the features is, to +/-13%, Deltanu/nu=cn(E-e) where c=-0.027 and n(E-e) is the Bose-Einstein population factor with E-e=860 cm(-1). The intensities of the optical absorption involving the creation of two phonons of energies E-1 and E-2 are expected to increase with T in proportion to [1+n(E-1)][1+n(E-2)]. This expression, combined with the fractional shift rule for the energies of each mode, allows high temperature two-phonon spectra to be simulated accurately from a low temperature spectrum. The temperature dependence of the three-phonon band between 2665 and 3900 cm(-1) is precisely fitted without adjustable parameters by using the shift rule in conjunction with a modified density of three-phonon states. Absorption at 10.6 mum is shown to involve the simultaneous destruction and creation of phonons. Its strong temperature dependence in the range 300<T<800 K is accurately described, without any adjustable parameters, in terms of three main components: the destruction of one phonon of 335 cm(-1) and the creation of a second of 1275 cm(-1); the shift to lower energy of the phonons; and a three-phonon process involving the destruction of one and the creation of two phonons. The analysis demonstrates why diamond has to be effectively cooled when used for the windows of a high-power CO2 laser. (C) 2002 American Institute of Physics.
Notes: Univ London Kings Coll, Dept Phys, London WC2R 2LS, England. QinetiQ, Malvern WR14 3PS, Worcs, England. Univ Limburg, Inst Mat Res, B-3590 Diepenbeek, Belgium. De Beers Ind Diamonds Ltd, Ascot SL5 8BP, Berks, England.Piccirillo, C, Univ London Kings Coll, Dept Phys, London WC2R 2LS, England.
URI: http://hdl.handle.net/1942/2520
ISI #: 000176600000014
ISSN: 0021-8979
Category: A1
Type: Journal Contribution
Validation: ecoom, 2003
Appears in Collections: Research publications

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