williams potential

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elephant gogogo!

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Dec 9, 2022, 7:07:12 AM12/9/22
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Dear CP2K users,

I have found 5 different potentials from the literatures, but when I use it in the cp2k, it will always have the mistakes, e.g.,geometry wrong. I assume, maybe the potential is not so accurate or not suitble for cp2k. So how could I deal with this problem? Please find one of my inputs in the attachment.

Thank you for your time!
ceo2-1.inp

Krack Matthias (PSI)

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Dec 9, 2022, 11:40:46 AM12/9/22
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Hi

 

The force field is not properly defined in your input, e.g. a SHELL_CHARGE is set but no CORE_CHARGE. It is difficult to check the other parameters, because you did not specify the force field parameters for CeO2 which you want to use. The &CHARGE sections for rigid ion potentials should not appear when you specify &SHELL sections for a core-shell model. There is also no need to specify initially in addition to the &COORD section a &SHELL_COORD and a &CORE_COORD section. The &KIND sections can be dropped, because these are not considered by the Fist module. I am also not sure, if the lattice vectors and the atomic coordinates are matching and thus will represent the fluorite structure of CeO2 with PBC properly.

 

Best

 

Matthias

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elephant gogogo!

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Dec 9, 2022, 4:02:02 PM12/9/22
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Thank you matthias, I just get the potential from the literature, the literature only use the shell charge, so I don't know how to fix this mistake. But for the charge section, the potential has also columbic potential, so I should define the charge?

Best Regards

Krack Matthias

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Dec 10, 2022, 11:51:03 AM12/10/22
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CORE_CHARGE and SHELL_CHARGE must sum up to the desired formal charge which is usually +4 or +3 for Ce. Just take one of the UO2 test inputs for the CP2K/Fist module and fill in the units and values from the force field parameter table in the literature. Both CeO2 and UO2 have the same fluorite structure and you can substitute U by Ce. I would also cross-check the force field parameters with other papers, because such tables contain often typos.

 

HTH

elephant gogogo!

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Dec 12, 2022, 3:13:16 AM12/12/22
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ok,thank you a lot! I will check it again!
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