[CP2K-user] [CP2K:21961] Re: XAS calculation of an open-shell system

[qing zhou]

Dear Nanchen,

Based on your advice, I've successfully finished the calculation. Thanks so 
much for your help!

Have a nice day!

Best,
Qing_Zhou

在2025年11月13日星期四 UTC+8 17:32:34<Nan Dong> 写道：

> Hi qing zhou, 
>
> I checked your input and the output, and the spectrum. 
> In spectrum, there is only one state at 6167.202695 eV, which I would say 
> it bad but not so bad. 
> but the only one state should be noticed, which it is due to you set 
> ENERGY_RANGE 30. The expected Fe 1s around 7000, is out of this range tooo 
> far. 
> and I would suggest: 
> 1. increase the Grid size.  *GRID Fex 500 1000 *
> 2. decrease the number for searching, *N_SEARCH 5  *
> Because you only have one Fe here, and calculate its 1s excitations. The 
> MOs order should be Fe_1s, at the lowest. 
> 3. increase *RI_REGION* (you can test, ending up to contain all atoms in 
> the structure) 
> 4. maybe increase the *ENERGY_RANGE*, I would suggest 1000 or 2000. since 
> now your first excitation state is 6167, the range should include the 
> expected states (for Fe 1s 7000 eV approximately). After you improve the 
> first excitation energy, it can be reduced. 
>
> another option, decrease HF portion. PBE0(25%) or B3LYP(25%) might give a 
> better spectrum, which I preferred for Fe 2p spectrum. 
>
> Best, 
> Nanchen 
>
>
>
> 在2025年11月13日星期四 UTC+1 06:19:15<qing zhou> 写道：
>
>> Dear CP2K users and developers,
>>
>> I am using CP2K to calculate the XAS of an open-shell system with a spin 
>> multiplicity of 2. The OT method was enabled for the SCF calculation to aid 
>> convergence, and I have set EXCITATIONS OS_SPIN_CONS in the &XAS_TDP 
>> section. For the functional, I am using a PBE-based functional with 45% 
>> Hartree-Fock exchange. The def2-TZVP basis set was used for the Fe atom, 
>> while the DZVP-MOLOPT basis set was used for all other atoms.
>>
>> As shown in the output file, the calculation finished without any errors, 
>> and the SCF converged successfully. However, the excitation energies in the 
>> resulting spectrum file are obviously incorrect. I recall that the energy 
>> for the Fe K-edge should be around 7000 eV. Furthermore, the spectrum file 
>> contains only a single data point.
>>
>> I would like to ask what potential issues might exist in my calculation 
>> setup. How can I adjust my settings to correctly obtain the XAS spectrum 
>> for this open-shell system?
>>
>> I have attached my input (.inp), output (.out), and spectrum files for 
>> your reference. Thank you for your help!
>>
>

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