[DFTB-Plus-User] Dispersion and plots

[Bálint Aradi]

Dear Hegoi,

> 1.- Regarding dispersive forces. I am working on crystalline calcium hydroxide. It is a laminar compound, and the layers are suppose to interact via dispersive forces. When I run SCC CG calculations, the interlaminar distance decreases 12%. It is clear that the forces between layers are not very well described. Therefore, I tried to include the dispersion, but the interlaminar distance increases now up to 12%, no matter if I use the Lennard-Jones, the UFF or the slater-kirwook method. Any clue on what could I do?

 That's difficult for me to on this, as I'm not using dispersion in any
of my calculation. Both dispersion models, had been rather tested for
organic molecules and for H2 on various carbon constructs. I do not
think, any experience exist for your systems.
> 
> 2.- Regarding visualization, Is there any way to plot 3D density contours? or 3D plots of Homo-Lumo orbitals? 

  Sure, you can use Waveplot

http://www.dftb-plus.info/tools/waveplot/

to generate Cube-files, which can then visualize with several molecular
visualizer tools. (I usually use VMD for that purpose.)

  Best regards,

  Bálint

-- 
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/en/~b_aradi


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