[sdpd] size and strain analysis

[Guilhem DEZANNEAU <guilhemdezanneau...@yahoo.fr>]

Hi,

Many  of the messages sent in this discussion groups
deal with grain size and microstrain determination.
Unfortunately, it seems that the information is mainly
adressed to specialists. If i want to ?standardise?
grain size and strain determination for
non-cristallographer, what are the steps to do ¿? It
seems that Rieveld is the better way to obtain
non-user-dependent results but it is quite hard to
teach to non crystallographer ?thus, most of the
questions below deal with a peak by peak analysis

1-instrumental resolution

the pseudo-voigt function used for resolution function
determination on standard compounds do not allow to
fit the asymetry observed at low angle. Does it matter
really if i do not take into account this asymetry ¿?
Is one side of the peak more significant than the
other ¿?

The split pseudo-voigt function gives better results
but the ?splitting ? parameters show a tendency to
oscillate which would make difficult the analytical
resolution function expression.

2- powder analysis

how to subtract the resolution function from the
fitted pseudo-voigt function since it is a mixture of
gaussian and lorentzian.

Does the williamson-hall method involves the FWHM or
the integral width ¿?


Thanks

Guilhem DEZANNEAU





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