Abstract

A method is given for the location of certain types of stationary value of a function of many variables under conditions which make it applicable to atomistic modelling of crystal defects, for calculation of migration energies. The method, an adaptation of the conjugate gradients method of function minimization locates equilibrium configurations which have one unstable mode of vibration. It does not depend for its success on constraint of any coordinate of the system or on symmetry in the structure. Like the conjugate gradients minimization method, it requires evaluation of first, but not second, derivatives of the objective function. Examples are given of its application to the Frenkel-Kontorova model of a dislocation, and to the propagation of a crack in a brittle crystal.

Keywords

Saddle pointDislocationConstraint (computer-aided design)MinificationFunction (biology)Point (geometry)Crystallographic defectSaddleSymmetry (geometry)Stationary pointClassical mechanicsStatistical physicsVibrationPhysicsMathematical analysisMathematicsMathematical optimizationGeometryCondensed matter physicsQuantum mechanics

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Publication Info

Year
1974
Type
article
Volume
7
Issue
5
Pages
864-870
Citations
74
Access
Closed

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J. E. Sinclair, R. Fletcher (1974). A new method of saddle-point location for the calculation of defect migration energies. Journal of Physics C Solid State Physics , 7 (5) , 864-870. https://doi.org/10.1088/0022-3719/7/5/009

Identifiers

DOI
10.1088/0022-3719/7/5/009