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Temperature variation of the grüneisen parameter in magnesium oxide

Ganesan, S (1962) Temperature variation of the grüneisen parameter in magnesium oxide. In: Philosophical Magazine, 7 (74). pp. 197-205.

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Official URL: http://www.tandfonline.com/doi/abs/10.1080/1478643...


The thermal expansion of magnesium oxide has been measured below room temperature from 140°K to 284.5°K, using an interferometric method. The accuracy of measurement is better than 3% in the temperature range studied. The agreement of these results with Durand's is quite good, but consistently higher over most of the range by 2 or 3%, for the most part within the estimated experimental error. The Grüneisen parameter remains constant at about 1.51 over the present experimental range; but an isolated measurement of Durand at 85°K suggests that at lower temperatures it rises quite sharply above this value. This possibility is therefore investigated theoretically. With a non-central force model to represent MgO, γ(−3) and γ(2) are calculated and it is found that γ(−3) > γ(2), again suggesting that the Grüneisen parameter increases with falling temperature. Of the two reported experimental values for the infra-red absorption frequency, correlation with the heat capacity strongly indicates a wavelength of 25.26μm rather than 17.3μm. Thermal expansion measurements at still lower temperatures must be carried out to confirm definitely the rise in the Grüneisen parameter.

Item Type: Journal Article
Publication: Philosophical Magazine
Publisher: Taylor and Francis Group
Additional Information: Copyright of this article belongs to Taylor and Francis Group.
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 23 Feb 2012 06:15
Last Modified: 23 Feb 2012 06:15
URI: http://eprints.iisc.ac.in/id/eprint/43190

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