0 Take all bands to calculate the charge density, even unoccupied bands are taken into account.

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hszhao.cn@gmail.com
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0 Take all bands to calculate the charge density, even unoccupied bands are taken into account.

#1 Post by hszhao.cn@gmail.com » Wed May 11, 2022 3:07 pm

I noticed the following description here:
NBMOD = [integer]
Default: NBMOD = -1

Desription: Controls which bands are used in the calculation of Band decomposed charge densities. Check also IBAND and EINT.

This integer variable can take the following values:

>0 Number of values in the array IBAND. If IBAND is specified, NBMOD is set automatically to the correct value (in that case NBMOD should not be set manually in the INCAR file).

0 Take all bands to calculate the charge density, even unoccupied bands are taken into account.

-1 Calculate the total charge density as usual. This is the default value if nothing else is given.

-2 Calculate the partial charge density for electrons with their eigenvalues in the range specified by EINT.

-3 The same as before, but the energy range is given vs. the Fermi energy.
Regarding the above description, what I feel most difficult to understand is the option below:

0 Take all bands to calculate the charge density, even unoccupied bands are taken into account.

What is the point of taking unoccupied bands to calculate the charge density?

Regards,
HZ

andreas.singraber
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Re: 0 Take all bands to calculate the charge density, even unoccupied bands are taken into account.

#2 Post by andreas.singraber » Wed May 25, 2022 9:25 am

Hello!

I asked my colleagues if there was any application to this setting but it seems it was introduced as a debugging option and as such stayed selectable via the INCAR tag.

All the best,
Andreas Singraber

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Re: 0 Take all bands to calculate the charge density, even unoccupied bands are taken into account.

#3 Post by hszhao.cn@gmail.com » Tue Jun 07, 2022 5:48 am

In this sense, it has no practical application value, just for the convenience of code development and debugging.

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