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Transition-State Model for Entropy-Limited Freezing

Published online by Cambridge University Press:  28 February 2011

J. Y. Tsao ,
M. J. Aziz ,
P. S. Peercy  and
M. O. Thompson
J. Y. Tsao
Affiliation:
Device Research Dept., Sandia National Labs, Albuquerque, NM 87185
M. J. Aziz
Affiliation:
Div. of Applied Sciences, Harvard University, Cambridge, MA 02138
P. S. Peercy
Affiliation:
Device Research Dept., Sandia National Labs, Albuquerque, NM 87185
M. O. Thompson
Affiliation:
Dept. of Materials Science, Cornell University, Ithaca, NY 14853
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Abstract

A brief review is given of transition-state theory, both for the case of unimolecular reactions in the gas phase, and for reactions in condensed phases. An argument is made that, within the context of this theory, heterogeneous freezing in Si is limited to rates much lower than collision rates by the difference between the entropies of the solid and the liquid.

Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 74: Symposium A – Beam-Solid Interactions and Transient Processes , 1986 , 117
Copyright
Copyright © Materials Research Society 1987

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References

[1] Glasstone, S., Laidler, K.J. and Eyring, H., Theory of Rate Processes (McGraw-Hill, New York, 1966); and H. Eyring, S.H. Lin and S.M. Lin, Basic Chemical Kinetics (Wiley-Interscience, New York, 1980).Google Scholar
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[3] Christian, J.W., The Theory of Transformations in Metals and Alloys, 2nd Ed. (Pergamon Press, Oxford, 1975), Chap. 3.Google Scholar
[4] Tsao, J.Y., Aziz, M.J., Thompson, M.O. and Peercy, P.S., Phys. Rev. Lett. 56, 2712 (1986); and manuscript submitted to Phys. Rev. B.Google Scholar
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[6] Tsao, J.Y., Peercy, P.S. and Thompson, M.O., J. Mater. Res., to be published.Google Scholar
[7] Tsao, J.Y., Peercy, P.S. and Thompson, M.O., unpublished.Google Scholar
[8] It is also possible that transition-state theory alone is inadequate, and that other theories (or combinations of theories), such as those suggested by Bucksbaum, P.H. and Thompson, M.O. (to be published), and by Richards, P.M. (to be published), may be necessary.Google Scholar
[9] This is an asymmetry additional to that which might already be present due to an activation enthalpy.Google Scholar
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[11] In step 1, especially at high pressures, the strong-collision approximation (one-step activation) is usually made: a thermal population distribution is assumed to be established after each collision.Google Scholar
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[13] We assume that, in condensed phases under normal atmospheric pressure conditions, enthalpies are approximately equal to energies.Google Scholar
[14] These two assumptions represent important differences between the ideas presented here and those of Bucksbaum, P.H. and Thompson, M.O. [8]Google Scholar
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