RE: GSAS soft constraints

GREGOR@unisi.it
Wed, 31 Jul 1996 10:06:12 +0200 (WET-DST)

On Mon, 29 Jul 1996 17:45:51 +0200
Volker Kahlenberg <vkahlen@uni-bremen.de>
Universitaet Bremen
Fachbereich Geowissenschaften ( Kristallographie)
Klagenfurterstrasse, D - 28359 Bremen
wrote:
...using the GSAS soft constraint utility for the first time I have problems
with the creation of the special histogram containing the interatomic
distances as descibed on page 163 of the manual....

Dear Volker,
you don't have to care about the fact that distances are considered a histogram
- just enter them along with their estimated errors in the corresponding menu
option. We use e.g. d(Si-O)= 161+-1 pm, d(O-O )= 270+-5 pm for silicate tetra-
hedra. Then, there is an overall ponderation factor which puts the distance
histogram a weight relative to the intensity histogram(s). Try values from
1 to 100000, you should get it.
For more info, please specify the problem you have,
good luck!

Prof. Miguel Gregorkiewitz
Dip Scienze della Terra, Universita
Via delle Cerchia 3, I-53100 SIENA, Europe
fon +39'577'298823 fax 298815
email gregor@unisi.it
on leave at:
Prof. Miguel Gregorkiewitz
Inst Ciencia de Materiales, CSIC
E-28049 MADRID-Cantoblanco, Europe
email immmg18@cc.csic.es