Beginner Question: Electron Density Calculation

[xthought iso]

Hi Community,

Does VESTA allow me to take 2 similar materials and compare their electron densities?  If so, can someone give me general instructions on how to accomplish this?   The materials are iso-structural with the primary difference being  that one material contains Sulfur and the other contains Selenium.  I am interested in learning how the electron density of nearby Fe atoms differs across the two compounds. 
 
Thanks Very Much.

PS  If I have not provided enough for someone to answer this question, I would happy to add some details.

[Philip Howie]

VESTA does not allow you to calculate electron densities from first principles.  It can be used to calculate electron densities from structure factor data, for example from X-ray diffraction data, though I've not used that functionality.

I've had quite a bit of success using a density functional theory (DFT) code called SIESTA to calculate electronic structures from first principles.  Perhaps that sort of approach would be suitable for your materials.  In that case, I've found VESTA very useful for displaying the calculated densities as volumetric data and easily visualising them.

Philip