Journal of Applied Crystallography

Volume 41, Part 3 (June 2008)

research papers

J. Appl. Cryst. (2008). 41, 531-536 [ doi:10.1107/S0021889808005463 ]

Error estimates on bond-length and angle corrections from TLS analysis

J. Haestier, M. Sadki, A. L. Thompson and D. Watkin

Abstract: Librational motion within a crystal structure distorts the measured bond distances and angles from their physical values. TLS analysis of a rigid molecule or a rigid part of a molecule allows the calculation of bond-length and angle corrections. Until now, no estimate of the error on these corrections has been available. A method is presented for propagating the errors on the anisotropic displacement parameters (ADPs) to the bond-length and angle corrections which are a function of the libration tensor. The numerical significance of approximations made during the calculation is discussed.

Keywords: libration tensor; TLS analysis; bond-length and angle corrections.