AUTOINDEXING OF MULTIPHASE POLYCRYSTALS. V.B.Zlokazov FLNP JINR, 141980 Dubna, Moscow region, Russia. E-mail: Zlokazov@main1.jinr.dubna.su

Let a set of interplanar spacings (d_j), j = 1,2,..,m be given, which are diffraction reflections from a n-phase polycrystal. The autoindexing problem is solved by minimizing the following functional

(1)

The first member is

(2)

where = index values, minimizing expressions

(3)

and is a formula, describing reflections; (₁ and (₂ are uadratic, or robust, or entropy metrics. At the same time , computed while minimizing R_j, index jth reflections. V and N are volumes of a phase and total number of reflections at tried parameter vectors.

The minimization of (1) with respect to is carried out by trying parameter values from a assumed region, and refining them by analytical fitting, which, in case of convergence, gives the best estimate, or, if initial guesses are good enough, by analytical fitting.

Reference: Zlokazov V.B. Comp.Phys.Comm.,1995,v.85,p.415-422.