[CP2K-user] DFT+U calculations for Cr3+ in MgCl2-KCl melts
Xiaomei He
xiaome... at gmail.com
Fri Dec 13 22:24:56 UTC 2019
Dear Slava,
Can I ask you a question?
I want to applied DFT+U method too, but I don't kown how to measure
U_MINUS_J value , I find in you case the value is only 0.1234777, So what
dose 'J' mean and how to calculate?
Thank you very much.
Xiaomei
在 2019年4月24日星期三 UTC-4下午12:22:27，Vyacheslav Bryantsev写道：
>
> Dear CP2K Group,
>
> There are a couple of ways to setup antiferromagnetic calculations for 6
> Cr3+ ions (3d3 state) dissolved in MgCl2-KCl melt.
>
> One way is to use MAGNETIZATION keyword. Another way is to use the BS
> section (commented below)
>
> &KIND Cr1
> ELEMENT Cr
> BASIS_SET DZVP-MOLOPT-SR-GTH
> POTENTIAL GTH-PBE-q14
> *MAGNETIZATION 4.0*
> &DFT_PLUS_U
> L 2
> U_MINUS_J 0.1234777
> # U = 3.36 eV
> U_RAMPING 0.01234777
> &END DFT_PLUS_U
>
>
>
>
>
>
>
>
>
>
> *! &BS ! &ALPHA ! NEL +1 -1 ! L 2 0 !
> N 3 4 ! &END ALPHA ! &BETA ! NEL -5 -1 ! L 2 0 !
> N 3 4 ! &END BETA*
> &END BS
> &END KIND
> &KIND Cr2
> ELEMENT Cr
> BASIS_SET DZVP-MOLOPT-SR-GTH
> POTENTIAL GTH-PBE-q14
> *MAGNETIZATION -4.0*
> &DFT_PLUS_U
> L 2
> U_MINUS_J 0.1234777
> # U = 3.36 eV
> U_RAMPING 0.01234777
> &END DFT_PLUS_U
>
>
>
>
>
>
>
>
>
>
> *! &BS! &ALPHA! NEL -5 -1! L 2 0! N 3
> 4! &END ALPHA! &BETA! NEL +1 -1! L 2 0! N
> 3 4! &END BETA*
> &END KIND
>
> The problem I have is that the total E from two setups (MAGNETIZATION and
> BS) can be somewhat different:
> For example, the Etot of a system (mol fractions are shown) is lower when
> setting up calculations using BS
> 50-MgCl2-50-KCl-5-CrCl3
> Etot = -8997.64290729994173 using BS section
> Etot = -8997.62650294793639 using MAGNETIZATION keyword
>
> However, for a different composition, the Etot is lower using
> MAGNETIZATION
> 15-MgCl2-85-KCl-5-CrCl3
> Etot = -6895.30145964661006 using BS section
> Etot = -6895.31001188029859 using MAGNETIZATION keyword
>
> The resulting spin moment on each Cr3+ in both cases are close to +3 and
> -3, as expected.
>
>
> *What are the general recommendations to correctly find a ground
> electronic state using DFT+U for transition metal ions in solution/melts?*
>
> *Are there any additional checks one can do to make sure the ground
> electronic state is found?*
> After the ground electronic state is found, the next step will be to run
> AIMD simulations.
> The input and output files for these examples are given as attachments.
>
> Thank you,
> Slava
>
>
>
>
>
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