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QuantumATK => General Questions and Answers => Topic started by: hhspace on December 19, 2009, 13:12

Title: Pulay mixing inversion failed. Using only last step
Post by: hhspace on December 19, 2009, 13:12

    hello, everyone. When I calculate a isolated system more than 200 atoms, a problem happens and the message is given that "Pulay mixing inversion failed. Using only last step".
    Besides, the runtimeParameters gives:
sc 1 : Fermi Energy = 0.00000 Ry  Ebs =nan Ry dRho =0.0000E+00  dEbs = NAN Ry  dH =  0.0000E+00 Ry
......
sc 14: Fermi Energy = 0.00000 Ry  Ebs =nan Ry dRho =0.0000E+00  dEbs = NAN Ry  dH =  0.0000E+00 Ry
......

    How to deal with this problem? Thank you for any relies.

Title: Re: Pulay mixing inversion failed. Using only last step
Post by: Nordland on December 19, 2009, 14:33

Dear hhspace.

Something is wrong - very wrong.

If your system is a molecule ( I guess that is what your mean by isolated system. ), I would assume that you might have two atoms one top of one another.

I suggest that your share the configuration with us on the forum, and then I can perhaps find out what is the problem. If you are not interested in sharing the configiration with us, I would suggest contacting support at QuantumWise as I am sure it will be quick to resolve this issue for you.

Title: Re: Pulay mixing inversion failed. Using only last step
Post by: hhspace on December 20, 2009, 02:43

hi, Nordland. I just caltulate a magnetic molecule that has four Iron atoms. the problem happens just when I set the initial_spin = 5*hbar. However, when the initial_spin =1*hbar, everything is OK. So I think the key lies in the set of the initial_spin for this system.

Title: Re: Pulay mixing inversion failed. Using only last step
Post by: zh on December 20, 2009, 06:01

Try "initial_scaled_spin" to specify the initial spin of each atom.

Title: Re: Pulay mixing inversion failed. Using only last step
Post by: hhspace on December 20, 2009, 08:07

Well done! I solve this problem just using the initial_scaled_spin, and the result gives the spin taken as 5 hbar. But I really don't know why the initial_spin=5 hbar meet the problem.

Title: Re: Pulay mixing inversion failed. Using only last step
Post by: zh on December 20, 2009, 09:27

Quote

initial_spin=5 hbar

This means that you specify the initial total magnetic moment of whole system will be 5 hbar. Maybe, it is unreasonable initialization for your system.  You may check the results for the calculation with "initial_scaled_spin" and exact the obtained total magnetic moment (here assume that it is A hbar) of whole system. And then try to do a self-consistent calculation with "initial_spin= A hbar".

Title: Re: Pulay mixing inversion failed. Using only last step
Post by: hhspace on December 20, 2009, 13:34

Yes, I check the result for the calculation with "initial_scaled_spin" and it just gives the obtained total magnetic moment of the whole system as 5 hbar. But a self-consistent calculation with "initial_spin = 5 hbar"  still meets the above problem.

Title: Re: Pulay mixing inversion failed. Using only last step
Post by: zh on December 20, 2009, 13:42

Quote

And then try to do a self-consistent calculation with "initial_spin= A hbar".

Meanwhile, restore the charge density from the calculation with "initial_scaled_spin".