[Pw_forum] LDA+U

[Stefano Fabris]

Hi Sefa,

the problem is that you specify startingpot = 'file', which implies that 
both files, "iron.pot" and "iron.occup" are available. This is not the 
case. The procedure is to run also the initial LDA calculation with U=0, 
so specifying something like:
                    lda_plus_u = .true. ,
                  Hubbard_U(1) = 0.0,
                  Hubbard_U(2) = 0.0,
              Hubbard_alpha(1) = 0.0,
              Hubbard_alpha(2) = 0.0,
This allows you to understand which d states are occupied in a standard 
LDA calculation, and, as a byproduct, produce the "iron.pot" file. Now 
you are ready to modify the alpha parameters. Hope this helps.

Regards,
			Stefano.


sefa at fen.bilkent.edu.tr wrote:
> Dear Sir,
> 
> I am new user of PWSCF program.  I would like to use LDA+U routine for my magnetic system. Initially I wanted to check the program for Fe. I wanted to find U parameter for Fe. First I run program without U. After that I added U parameters in the input file. I prepared input file like that:
> 
>  &CONTROL
>                  calculation = 'scf' ,
>                 restart_mode = 'from_scratch' ,
>                       outdir = '/root/NEWPWSCF/examples/example13/results/nickel/IRON' ,
>                   pseudo_dir = '/root/NEWPWSCF/pseudo/' ,
>                       prefix = iron ,
>  /
>  &SYSTEM
>                        ibrav = 2,
>                            A = 5.65 ,
>                            B = 5.65 ,
>                            C = 5.65 ,
>                        cosAB = 0 ,
>                        cosAC = 0 ,
>                        cosBC = 0 ,
>                          nat = 2,
>                         ntyp = 2,
>                      ecutwfc = 35 ,
>                      ecutrho = 420 ,
>                         nbnd = 15,
>                  occupations = 'smearing' ,
>                      degauss = 0.005 ,
>                     smearing = 'methfessel-paxton' ,
>                        nspin = 2 ,
>    starting_magnetization(1) = 0.7,
>    starting_magnetization(2) = 0.7,
>                   lda_plus_u = .true. ,
>                 Hubbard_U(1) = 0.0,
>                 Hubbard_U(2) = 0.0,
>             Hubbard_alpha(1) = 0.1,
>             Hubbard_alpha(2) = 0.0,
>  /
>  &ELECTRONS
>                     conv_thr = 1.0e-12 ,
>                  startingpot = 'file' ,
>                  startingwfc = 'file' ,
>                  mixing_mode = 'potential' ,
>                  mixing_beta = 0.2 ,  
>              diagonalization = 'david' ,
>               diago_thr_init = 6.52e-10 ,
>  /
> ATOMIC_SPECIES
>   Fe1   55.84700  Fe.pz-nd-rrkjus.UPF 
>   Fe2   55.84700  Fe.pz-nd-rrkjus.UPF 
> ATOMIC_POSITIONS alat 
>   Fe1      0.000000000    0.000000000    0.000000000    
>   Fe2      0.500000000    0.500000000    0.500000000    
> K_POINTS automatic 
>   8 8 8   0  0  0
> 
> 
> When I run the program It gave this error message:
> ---------------------------------------------------------------------
> forrtl: severe (24): end-of-file during read, unit 14, file /root/NEWPWSCF/examples/example13/results/nickel/IRON/iron.occup
> Image              PC        Routine            Line        Source             
> pw.x               084F40A8  Unknown               Unknown  Unknown
> pw.x               084F390C  Unknown               Unknown  Unknown
> pw.x               084D1DDD  Unknown               Unknown  Unknown
> pw.x               08496348  Unknown               Unknown  Unknown
> pw.x               084967EB  Unknown               Unknown  Unknown
> pw.x               084AF4CE  Unknown               Unknown  Unknown
> pw.x               080DD118  Unknown               Unknown  Unknown
> pw.x               080B3DC1  Unknown               Unknown  Unknown
> pw.x               0804B248  Unknown               Unknown  Unknown
> pw.x               420158D4  Unknown               Unknown  Unknown
> pw.x               0804B101  Unknown               Unknown  Unknown
> -------------------------------------------------------------------------------
> 
> Can you explain what is the meaning of this error? Where do I made a mistake?
> 
> Thank You for Your help
> Yours Sincerely,
> Sefa Dag
> 
> 
> 
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-- 
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Stefano Fabris                               fabris at democritos.it
INFM DEMOCRITOS - SISSA                      tel: +39 040 3787405
via Beirut 2-4, I-34014 Trieste, Italy       fax: +39 040 3787528
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