Regarding ISOValues [in particular charge density]

[lamkt]

Dear all,

Let me refer to a previous post http://quantumwise.com/forum/index.php?topic=126.0
{I'm starting a new one so as not to hijack others' topic}

I would like to know if I can modify the Bloch state [aka wavefunction, phi] calculated {as a function of energy determined by the quantum number, i.e. band number and k-vector} into the charge density {which will also be a function of energy}.

I'm guessing that this would be different from the electron density calculated since that would be summed over all energy and is also dependent on the electron occupancy.  Or can I get the charge density from electron density and occupancy?

Thank you in advance for any info.

[Anders Blom]

You could take [tex]\left|\Psi_{E,{\bf k}}({\bf r})\right|^2[/tex] as some kind of measure of the electron density (k-point resolved), but as you point out the real charge density is the weighted average over k-points and occupancy. However, I'm not sure why you distinguish between the charge density and the electron density, which ATK will give you?

[lamkt]

I'm thinking more of the LUMO/HOMO (or the conduction band, valance band) for a periodic structure.  That is different from the isoplot for electron density since I can't control the quantum state {band number, k-vector) for that calculation.  I can control the quantum state for wavefunction calculation with is related to the charge density so I was thinking maybe it would be possible to just square the value from wavefunction and plot that as the charge density.

But then again I've got the problem of choosing what isovalue to plot and what information I'm trying to obtain from the plot.

Anyway thanks for the reply.  I'm just thinking aloud on the best way to present the data for some conclusion.

[Anders Blom]

For reference, when you plot complex quantities in VNL you have a choice of plotting by magnitude or phase. So you can obtain the plot you are looking for without doing any manual scripting to square the wavefunction. Then, as you say, it's a matter of interpreting it...

"Thinking aloud" is to me a perfect description of one of the purposes of this Forum, so please continue to do that!