Mulliken Population analysis

[guodudu]

Hi, everyone

I saw in this topic that you can use 'MullikenPopulation.atomicCharge().sum()'  to calculate the total charge of the device.
https://forum.quantumatk.com/index.php?topic=7116.msg29196#msg29196

However, for the same mulliken population, the manual sum and the .py give a different magnitude of data, the .py gives a result of about a few tenths of e, and the manual sum of this total is more than that. What is the unit manually added, is there any conversion relationship in it, or should the value of total not be added?

Thank you for your answer.

[guodudu]

Not just these two atoms in the picture, incomplete

[Anders Blom]

I think you are mixing up total charge and net charge. The "sum" version gives the sum of the differences of the Mulliken charges and the neutral atom charges (i.e. the net charge of the central region), but summing manually just gives you the total Mulliken charges (total number of electrons in the central region).

[guodudu]

Thank you for your help.

If I want to calculate the net charge of some of these atoms, what should I do?(i.e. the net charge of designated region)

Wish you have a nice day!

I think you are mixing up total charge and net charge. The "sum" version gives the sum of the differences of the Mulliken charges and the neutral atom charges (i.e. the net charge of the central region), but summing manually just gives you the total Mulliken charges (total number of electrons in the central region).

[Anders Blom]

This is exactly what the query method atomicCharge() returns, you just need to sum over some atoms and not all