I think that what you refer to as CELIUS could in fact be Cerius2 or its
predecessor CERIUS. Cerius2 is a UNIX-based molecular modelling package,
consisting of a wide range of crystal structure visualisation and manipulation
tools, and many computational modules, including interfaces to other well-known
computational tools such as Gaussian, MOPAC, and for Rietveld, a full interface
to DBWS and a looser interface to GSAS. Also included is a comprehensive
diffraction simulation package.
The program is developed and marketed by Biosym / Molecular Simulations, the
company with which I work !
I cannot remember the reference to CELIUS which you mention - if I'm wrong in
assuming that the reference was actually to Cerius2 or CERIUS, please somebody
correct me.
Best wishes,
Dr. Steve Maginn,
Biosym / Molecular Simulations,
Cambridge, UK