[Ape-users] Problems when performing all-electron calculation using MGGA functional

[Micael Oliveira]

Dear Yi,

  It seems that at a certain point during the SCF cycle the code is 
unable to find the eigenvalue for a given state and this usually means 
that the state is unbound. In this case, my guess is that the problem 
comes from the asymptotic limit of the Tran-Blaha MGGA, which will be a 
problem for APE if it implies that the eigenvalue of a given state 
becomes positive.

  In the case of the Becke-Johnson MGGA we found a way of getting around 
this problem, but unfortunately we did not implemented it for the Tran 
-Blaha functional. In principle this should be fixed in the next release 
of the APE. To be sure this is the problem, maybe you could try the 
Becke-Johnson functional and see if it works. Also, this functional 
should give better results for atoms than the Tran-Blaha one.

  Best regards,

Micael


On 11/08/2010 01:04 PM, gaoy at aphy.iphy.ac.cn wrote:
> Dear APE developers and users,
>
> I am very sorry that the last mail concerning the same problem is not complete. Following is the complete description of my problem.
>
> It is amazing and awesome work that ape-1.1.0 incorporated more functionals including MGGA. However, I got a problem when performing all-electron calculation using MGGA functional.
>
> For calculating element Silicon, the following "inp-ape" file was prepared:
>
> ###########################################################################
> Title = 'Silicon'
> CalculationMode = ae
> Verbose = 40
> TypeOfMixing = 1
> Mixing = 0.05
> EigenSolverTolerance = 1.0e-5
> XCFunctional = 208012
>
> NuclearCharge = 14
> %Orbitals
>   "Ne"
>   3 | 0 | 2 | 0
>   3 | 1 | 2 | 0
>   4 | 0 | 0 | 0
> %
> ###########################################################################
>
> The calculation can be started but after a few iteration, the program terminated, presenting the error message:
>
> ###########################################################################
> Fatal Error (description follows)
>    Unable to bracket eigenvalue for state: 3p
> ###########################################################################
>
> Does anyone have any idea on that?
>
> Thank you very much for attentions.
>
> Best wishes!
>
> Yi
>
> 2010.11.08
>
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