scaling up the calculated peaks

[Ramadas Sunil Pophale]

Hello everyone,

I am using GSAS for refinement of a zeolite + template assembly. During
the 1st few cycles of the refinement, the calculated peaks I am getting
are very small although apparently in the right positions. The difference
between the observed and calculated intensities is almost an order of
magnitude. Refining the profile type and coefficients is not making much
of a difference. Since I have no clue as to why there is such a
difference, I wanted to simply scale up the calculated values to see
how they match up with the observed peaks. I tried using powplot and
liveplot, but could not figure out a way to do it. Is such thing possible
with GSAS?

Thanks for your attention.

Regards,

Ramdas Pophale.

ps: I am using the template as part of the phase with bond constraints. Is
it reasonable to refine the template along with the zeolite in the early
stages?

RE: scaling up the calculated peaks

[Von Dreele, Robert B.]

Dear Ramadas,
Sometimes getting a Rietveld refinement to start is hard. You might try
guessing at what you think the scale ought to be (relative peak
heights would do) and set it to that value and not refine it (i.e. turn
off the refine flag). Then you might see what is really wrong (misset
lattice parameters?) that is keeping the refinement from starting. After
getting that straightened out then turn back on the scale refinement
flag.
Bob Von Dreele

R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne, IL 60439-4814



-Original Message-
From: Ramadas Sunil Pophale [mailto:[EMAIL PROTECTED] 
Sent: Friday, December 14, 2007 2:02 PM
To: rietveld_l@ill.fr
Subject: scaling up the calculated peaks



Hello everyone,

I am using GSAS for refinement of a zeolite + template assembly. During
the 1st few cycles of the refinement, the calculated peaks I am getting
are very small although apparently in the right positions. The
difference between the observed and calculated intensities is almost an
order of magnitude. Refining the profile type and coefficients is not
making much of a difference. Since I have no clue as to why there is
such a difference, I wanted to simply scale up the calculated values to
see how they match up with the observed peaks. I tried using powplot and
liveplot, but could not figure out a way to do it. Is such thing
possible with GSAS?

Thanks for your attention.

Regards,

Ramdas Pophale.

ps: I am using the template as part of the phase with bond constraints.
Is it reasonable to refine the template along with the zeolite in the
early stages?