charged systems

Asked by Maria on 2019-01-29

Dear all,

1/ When I do a spin polarized calculation of a charged systems (molecule, molecule+surface). What parameters, I should utilize :

netcharge only or they anoter parameter ?

2 / If Spinpolarized = .true. , is the system automatically converging to the most stable solution ? or, it must that I fix the total spin ?
Thank you in advance

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Nick Papior (nickpapior) said : #1

1) In 4.0 NetCharge is a viable solution, and maybe in combination with SimulateDoping. But you have to figure out what kind of system you want to simulate.

2) No, spin-polarized (collinear or non-collinear) is not guarenteed to converge to the minimum energy configuration since there may be local minima. It is the users responsibility to search the spin-space for the "true" minimum configuration.

Maria (maria11) said : #2

Dear Prof. Nick,

Thank you very much for your replay.

For the pseudopotentiels in the website of siesta (no relativistic), We can do a spinpolarised calculation with a non relativistic pseudopotentiel?

I wait your answer. Thank you again.

Maria (maria11) said : #8

Dear Prof. Nick,

I have another questions and I hope that you answer me :

1/ If I do a calculation of a charged molecule with non- cubic box. In the ouput file, I see the warning that the Madelung correction is not calculated.

So, my calcuation without this Madelung correction is correct and I ignore this warning ?? and the final energy is taken an accound this charge or not ??

2/ if I do the calculation of a system (adsorption of a charged molecule on surface). I also ignore this warning ??
how I can do?
Please clarify for me this point.

Thank you very much again.

Nick Papior (nickpapior) said : #9

It isn't important for your calculations.

Please do a litterature search for the Madelung correction if in doubt of what it does.

Can you help with this problem?

Provide an answer of your own, or ask Maria for more information if necessary.

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