# Parameters of FindAllAtomsInsideSphere()

asked by Matthias Able (2021/05/21 11:23)

Dear Developers,

I'm trying to build a clustur with this method as in the NiO workshop: NewCluster = FindAllAtomsInsideSphere(TB.Atoms,TB.Cell,{0,0,0},4)

What Koordinatesystem is used and what units should I use here? The documentation was a bit rare. http://www.quanty.org/documentation/language_reference/functions/findallatomsinsidesphere

Best regards Matthias Able

## Answers

Hello Matthias Able,

I am not a developer but I believe I may be able to help you with this question. If you are running the example code from the DFT MLFT workshop, you can try writing the lines

print(TB.Atoms)and

print(TB.Cell)in the 3_XAS.Quanty file.

You will see that the coordinate system of the cluster is xyz. The units are slightly more confusing; at first I thought they were Angstroms, but the value 3.94 from TB.Cell is a bit large for the normal Ni-O bond length, see https://materialsproject.org/materials/mp-19009/#. However, the Bohr radius is roughly twice an Angstrom, 1 Angstrom = 1.889 Bohr radii. If you divide 3.94 by 1.889, 3.94/1.889 = 2.08, which is the correct bond length of Ni-O in Angstroms.

To summarize, the coordinate system is xyz, and the units are Bohr radii. Best of luck.Sincerely, Charles Cardot

Sorry for the missing documentation

Quanty has by itself no units that it prefers. When I read a tight binding structure from DFT I copy the units and conventions used in that DFT code. When you define the tight binding structure you are allowed to use any units you like. Until I find the time to write the documentation, please use print statements to see how the variables are defined.

Best wishes, Maurits

Thanks for your kind answers.

Meanwhile, I found the problem, which was actually that the output file of the FPLO DFT calculations changed. So, the method FindAllAtomsInsideSphere() is not working for the current version fplo18.00-52. If anyone faces the same problem, please contact me. I wrote it now by myself.

Best regards, Matthias

What is the solution?

Best Miguel

Dear Miguel,

The tutorials on the workshop for 2022 (https://www.quanty.org/workshop/heidelberg/october_2022/programme) shows a working example with all versions of FPLO. You do need the latest Quanty version.

best wishes, Maurits

Dear Matthias,

Can you share the solution with me. I will do a coding session at the end of the summer also updating the FPLO interface such that it will work with version 18 again.

Best wishes, Maurits

are there news on a new Quanty version which works with FPLO18 and the new version?