LAUENORM - Internal Wavelength Normalisation
Abstract
The program LAUENORM is used to perform an internal wavelength
normalisation for one or more packs of Laue data based on symmetry
equivalent reflections measured at different wavelengths. It may
also be used to apply previously calculated normalisation curves to further
sets of Laue data. If more than one pack is input then the program will
refine the inter-pack scaling (and optionally temperature) factors.
An iterative procedure is carried out which alternates cycles of wavelength
normalisation and cycles of inter-pack scaling. The Laue reflection data are
split into user defined wavelength bins. Up to eight non-overlapping ranges
of bins may be defined to allow for discontinuities in the normalisation
function at absorption edges.
The internal R-factors for the Laue data are extensively analysed. The
normalised reflection data may either be written to an output file as a
merged set of data (MTZ format) or as an unmerged set of data suitable for
input to the CCP4 programs ROTAVATA/AGROVATA. An option is also available
to write a merged set of data to a file in a format suitable fo input to
SHELX.
LAUENORM has an option to take advantage of the variation of the
normalisation function with wavelength to deconvolute multiple reflections.
This is attempted when a reflection multiple has been measured with the
crystal in more than one orientation (i.e. at different wavelengths) or when
a symmetry equivalent multiple is present again at different wavelengths from
the first multiple. To deconvolute a double, two or more such orientations
are needed, three or more for a triple and so on.
Documentation
A user documentation file
is available in html format. The suite is distributed with a plain
text file equivalent.
Availability
The program is distributed as part of the
Laue Software Suite.
Contact
Quan Hao <:qhao@dmu.ac.uk>
John W. Campbell
CCLRC Daresbury Laboratory
Last update 21 August 1996