ISSN:
1600-5724
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
The general method of computing the intensities of diffuse scattering in electron diffraction patterns, outlined by Cowley & Pogany in Part I, has been applied to the case of diffuse scattering given by the short-range ordering in binary solid solutions. If the diffuse scattering from individual crystal slices, of thickness greater than the effective range of ordering, can be assumed to be kinematical, the total diffuse scattering can be expressed in terms of the usual short-range order parameters, αi, and `dynamical factors'. When the diffuse scattering from a slice cannot be assumed to be kinematical, as in the case of copper–gold alloys, a new type of order parameter, involving some higher-order correlations, must be introduced. Expressions are derived for the absorption coefficients which must be applied to the Bragg reflections. The intensity of diffuse scattering from a single slice of crystal is calculated for a simple domain model of short-range order to evaluate the order of magnitude of departures from kinematical scattering and the possible sensitivity of the diffuse intensity to higher-order correlations. The methods are outlined by which diffuse intensity could be calculated for the whole crystal by a modification of the n-beam dynamical multi-slice procedure and a procedure for the approximate calculation of multiple-diffuse scattering is suggested.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0567739468000653
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