Dear Ana,
maybe I am a little bit picky here, but actually you
cannot convert U(ij) into U(iso), because U(ij) result from
a fit with anisotropic displacement parameters, while
U(iso) results from a fit with isotropic displacement
parameters. Thus, to convert one into the other means
repeating the fit with a different model.
What you probably mean is how to convert U(ij) into
U(eqiv), which is something like simulating the
change in model mentioned above by calculating an
"equivalent isotropic atomic displacement parameter"
from the anisotropic one, for the sake of comparison
between isotropic and anisotropic parameters.
But as I said, I am very picky about the terminology
here, so please don't take that too serious. ;)
Details on the calculation can be found in the CIF
core dictionary of the IUCr:
http://ww1.iucr.org/cif/cifdic_html/1/cif_core.dic/Iatom_site_U_iso_or_equiv.html
Cheers,
Frank
Ana Isabel Becerro Nieto wrote:
Dear All,
How can I convert the “anisotropic temperature factors” (u_ij ) into an
“isotropic temperature factor” (U_iso )?
Thank you!
ana
Dr. Ana Isabel Becerro
Instituto de Ciencia de Materiales de Sevilla -
Dpto. Química Inorgánica (CSIC-US)
C/ Américo Vespucio, 49
41092 Sevilla
Tel: 954489545
