PRESENT STATE OF MRIA - A PROGRAM FOR THE RIETVELD ANALYSIS OF RTOF DIFFRACTION SPECTRA.

V.B.Zlokazov, A.M.Balagurov

FLNP JINR, 141980 Dubna, Moscow region, Russia
E-mail: zlokazov@main1.jinr.dubna.su, E-mail: bala@nf.jinr.ru

MRIA - a program for a full profile analysis of multiphase powder neutron diffraction was originally designed as the only peak shape independent and fast fit routine which made it indispensible for treating the time-of-flight RTOF (reversed time-of-flight) spectra[1]. However, the area of applications of RTOF methods being growing gradually new features were added to MRIA which widely extended the class of problems being solved by this program.

1. The mode for the analysis of neutron diffraction spectra obtained from the conventional neutron diffractometers (l = const) was implemented.
2. Techniques for taking into account the texture effects in the Rietveld analysis were added.
3. The treatment of magnetic diffraction for collinear structures was included.
4. The automatic three-dimensional peak search in Fourier synthesis has been developed [2].
5. The Rietveld analysis was extended to the case of the spectra with the intensities referred to d-values.

The report goes over these new features in more detail.

1. Zlokazov V.B., Chernyshev V.V., Journal of Applied Crystallography (1992) 25, 447-451
2. Zlokazov V.B. Journal of Applied Crystallography, (1997).30,p.996-1001