[Smeagol-discuss] supercell

[Ivan Rungger]

Dear Mohamed,

   a supercell is not always built in siesta, it depends on the size of
your unit cell, and on the cutoff radii. You have a warning about
multiply connected orbitals, which might be the origin of the error. You
might try to change the basis set (usually just the cutoffs), and set
NeglNonOverlapInt to False. Other than that it might be a problem with
the atomic coordinates.

Cheers,
 
Ivan
> Hi Ivan
> In all calculations I noticed that there are  Internal auxiliary
> supercell.  For example
>  Internal auxiliary supercell:     3 x     3 x     1  =       9
> But in some cases I did not see this. I see that
> siesta: k-grid: Number of k-points =    15
> siesta: k-grid: Cutoff             =    14.319 Ang
> siesta: k-grid: Supercell and displacements
> siesta: k-grid:    5   0   0      0.000
> siesta: k-grid:    0   5   0      0.000
> siesta: k-grid:    0   0   1      0.000
> siesta: overlap:  rmaxh   veclen  direction
> siesta: overlap:  16.0896 16.2353   1
> siesta: overlap:  rmaxh   veclen  direction
> siesta: overlap:  16.0896 16.2353   2
> siesta: overlap:  rmaxh   veclen  direction
> siesta: overlap:  16.0896 54.1177   3
>
> * Maximum dynamic memory allocated =     2 MB
>
> siesta:                 ===============================
>                             Begin MD step =      1
>                         ===============================
>
> xijorb: WARNING: orbital pair      1   744 is multiply connected
>
>
> InitMesh: MESH =    80 x    80 x   250 =     1600000
> InitMesh: Mesh cutoff (required, used) =   200.000   210.621 Ry
>
> * Maximum dynamic memory allocated =   852 MB
>  The leading minor of order           27  of B is not positive definite.
>  The factorization of B could not be completed
>   and no eigenvalues or eigenvectors were computed.
> Terminating due to failed diagonalisation
> Stopping Program
>
> what is the meaning of there is no the supercellcalculation? and
> because of there is no supercell calculation there is error.
> Best regards
>
>   


-- 
=================================================
Ivan Rungger,

School of Physics and CRANN,  
Trinity College Dublin,  
Dublin 2,  IRELAND  
Phone: +353-1-8968454  
Email: runggeri at tcd.ie
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