Hi Bruce,

Thanks for your reply. I am familiar with outer-sphere complexation and how it works but I am much less familiar with Artemis and how such question can be approached. In the past we used Excurve and DL-Excurve where you can simply name the backscatter with initial estimates of N and R but without any need for STRUCTURE. Now, having moved away from these tools into Demeter and Artemis I am trying to learn rather than asking people to do work for me!

So, what I have done so far was to replace Ti in the Atoms file by Ni but it is not clear to me what I need to change in order to test outer-sphere vs inner-sphere complexes of Ni.

space = P b c n
a     =   8.71280    b    =   5.23270    c     = 14.48700
alpha = 90.00000    beta = 90.00000    gamma = 90.00000
rmax =   7.84905    core = Ti
# polarization = 0.0 0.0 0.0
shift =     0.00000    0.00000    0.00000
atoms
# el.     x           y           z        tag
Na     0.06430     0.64500     0.15370   Na
Ti     0.15130     0.13220     0.33090   Ti
Si     0.34210     0.29610     0.52670   Si
O      0.00000     0.00600     0.25000   O1
O      0.18170     0.44070     0.27580   O2
O      0.33360     0.29670     0.41520   O3
O      0.00890     0.24280     0.42800   O4
O      0.23570     0.05980     0.56700   O5

Thanks,

On Thu, Jun 9, 2016 at 3:58 PM, Bruce Ravel <bravel@bnl.gov> wrote:

This is an very vague and open-ended question.

Have you read any of the very extensive literature applying EXAFS to outer-sphere complexation? Have you tried anything ... anything at all ... to solve your problem?

If you ask specific questions, you will get good answers. If you ask folks on the list to do your work for you, that won't go so well.

B

On 06/09/2016 10:25 AM, Gnu script wrote:

Dear All,

I am relatively new to Ifeffit and Artemis. I am trying to find a way to
create four-shell model of an outer-sphere complex in Atoms or some
other way readable by Atoms. I have no idea about the geometry, space
group but some rough guess of bond-distances. The model to test against
the EXAFS data is:
Ni is the central atom
Ni-O first shell
Ni-Ni second shell
Ni-Ti third shell
Ni-Si fourth shell

The model aims to test the adsorption of Ni on the surface of
Ti-containing silicate mineral.

Could you please help.

Thanks.

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--
Bruce Ravel ------------------------------------ bravel@bnl.gov

National Institute of Standards and Technology
Synchrotron Science Group at NSLS-II
Building 535A
Upton NY, 11973

Homepage: http://bruceravel.github.io/home/
Software: https://github.com/bruceravel
Demeter: http://bruceravel.github.io/demeter/
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