The Rietveld method using an experimental profile convoluted by adjustable analytical function
Abstract
<h2>Acta Crystallographica Section A</h2><h3>Foundations of Crystallography</h3><h3>0108-7673</h3> <h2>abstracts</h2> Volume 40 Supplement Page c369 July 1984 <h2>The Rietveld method using an experimental profile convoluted by adjustable analytical function</h2> A. Le Bail 12.5--6 THE RIETVELD METHOD USING AN EXPERIMENTAL PROFILE CONVOLUTED BY ADJUSTABLE ANALYTICAL FUNCTION. By A. Le Bail, Facult~ des Sciences du MANS, Laboratoire des Fluorures et Oxyfluorures loniques, Route de Laval, 72017 LE MANS CEDEX. The full potential of the Rietveld method as applied to the X-ray powder diffraction technique is not yet rea- lized because of unsuccess of analytical peak-shape functions. It is shown that conventional Rup value infe- rior to I0 % may be systematically obtained by a proce- dure combining the choice of an experimental profile for each compound and the refinement in shape and angular width variation of an analytical function convoluted with the former. Calculations are made with Fourier coefficients replacing the convolution by a more simple product ; for the choice of a standard g(X)eo centered at e ° and defined between -a/2 and a/2, any reflexion g(x, e) is obtainedfollowing the expression (for the even part) : +~ 2 T 2rnx ] E A n e-H0 n cos -- g(x, e) =