A new model for tetrahedral amorphous carbon (ta-C)

Walters, J.K. and Gilkes, K.W.R. and Wicks, James D and Newport, Robert J. (1997) A new model for tetrahedral amorphous carbon (ta-C). In: 7th International Conference on the Structure of Non-Crystalline Materials (NCM7), 15-19 September 1997, Cagliari, Italy. (Access to this publication is restricted)

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http://dx.doi.org/10.1016/S0022-3093(98)00395-0 ...

Abstract

We have developed the reverse Monte Carlo (RMC) modeling method to generate two physically acceptable models for tetrahedral amorphous carbon (ta-C). The models have been produced by fitting to experimental neutron diffraction data and by applying various constraints consistent with chemical and physical knowledge of the material, In particular, three different carbon atom types (tetrahedral, planar and linear) have been defined and a new approach to applying coordination number constraints has been developed, The models were generated from an initial random distribution of 3000 atoms and from these we have determined ring number and coordination number distributions that are statistically averaged over the whole structure, We are able to look in detail at the distribution of different types of carbon bonding sites within the box and at the effects of incorporating 5 at.% H into the structure. The new models show that atoms with sp2 bonds tend to cluster and form polymer-like chains, which interlink the regions of sp3 or diamond-like bonding. Also, the relative flexibility of these polymeric chains results in more porous, less dense regions of the network. A comparison with other models for ta-C is also made.

Item Type: Conference or workshop item (Paper)
Additional information: 7th International Conference on the Structure of Non-Crystalline Materials (NCM7) CAGLIARI, ITALY, SEP 15-19, 1997 Presidenza Giunta Reg; Reg Autonoma Sardegna, Assessorato Affari Gen; Camera Commercio Ind Artigianato & Agr; EMSA, Ente Minerario Sardo; Fdn Banco Sardegna; Univ Cagliari; CNR, Com Chim; INCM, Consorzio Interuniv Nazl Chim Mat; SARAS Raffinerie Sarde; Comune Iglisias; Assoc Univ Sulcis Iglesiente; Ente Sardo Ind Turistiche
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences > Functional Materials Group
Depositing User: J.M. Smith
Date Deposited: 14 May 2009 12:35
Last Modified: 18 Jul 2014 15:53
Resource URI: http://kar.kent.ac.uk/id/eprint/15987 (The current URI for this page, for reference purposes)
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