[Pw_forum] problem getting electronuc dipole moment

[Mousumi Upadhyay Kahaly]

Dear Sir,

            1.     I was actually trying to do these calculations for
different di-acetates molecules, where I am expecting
electronic dipole moment. As it failed, I was trying to test
the cause with H2 molecule. And, as I told, this is the case
for any molecule in any position within a box of any size. So,
I want to know if any mistake is there in my input files and
any extra flag is to be set for getting correct result.

            2.      I have even polarised the H2 molecule and found
similar result(charge density inside the WS cell = 0.00000000). By
changing the position of the H2 molecule in the box, I wanted to see  How
WS cell is contructed and whether any charge come within the WS cell.  How
is this possible that always the same 0.0000000 comes?

             Sir, will you please see if I made something wrong(or may be
I need to add some extra lines) in the input files?

                          Best regards,   mousumi.


> On Fri, 22 Jul 2005, Mousumi Upadhyay Kahaly wrote:
>
> MK> Dear All,
> MK>
> MK>           I am trying to compute electronic and ionic dipole moments
of an
> MK> isolated H2 molecule in a big box. For this, after relaxation, I MK>
am running one scf step followed by a pp.x run and then chdens.x MK>
run(with the option idpol = 1).
>
> MK>
> MK>           The problem is that, irrespective of the positions of the
H2
> MK> molecule in the big box, always it comes that charge density MK>
inside the Wigner-Seitz cell = 0.00000000 & hence, electronic MK> dipole
moment is sero. Have I done something wrong may be, while
>
> i may be missing something here, but the h2 molecule has
> no dipole moment (unless you polarize it).
>
> axel.
>
> MK> setting up the input files??? Because this is the case for any MK>
molecule in any position within a box of any size. Can anyone MK> please
help me to get rid of this problem?
> MK>
> MK>           All the inputs files i am using(one case: when the
molecule
> MK> centre is in the centre of the box) are written below.
> MK>
> MK>                                             Best regards,  mousumi.
MK>
> ==========================================================================
MK> 1. Input file for scf run: pw.x input file
> MK>
> MK>  &CONTROL
> MK>               calculation = 'scf' ,
> MK>                    tstress=.true.,
> MK>              restart_mode = 'from_scratch' ,
> MK>        outdir =
> MK> '/export/mousumi/PWSCF_2.0.1/H2/PostProcess/dipole_mom/tmp2//' , MK>
                  pseudo_dir = '/export/mousumi/PWscf_GUI/pseudo/' , MK>
                      prefix = 'H2' ,
> MK>  /
> MK>  &SYSTEM
> MK>                        ibrav = 1,
> MK>                    celldm(1) = 30.00000,
> MK>                          nat = 2,
> MK>                         ntyp = 1,
> MK>                      ecutwfc = 30.00000  ,
> MK>                      ecutrho = 180.00000 ,
> MK>                        nosym = .false. ,
> MK>                         nbnd = 5,
> MK>                        nspin = 1 ,
> MK>                   lda_plus_u = .false. ,
> MK>  /
> MK>  &ELECTRONS
> MK>                     conv_thr = 1.0d-8 ,
> MK>     /
> MK>  &IONS
> MK>                      upscale = 10.0 ,
> MK>  /
> MK> ATOMIC_SPECIES
> MK>     H    1.00000  H.pbe-van_bm.UPF
> MK> ATOMIC_POSITIONS {angstrom}
> MK> H        7.70055287150   7.70055287150   7.70055287150
> MK> H        8.15472682850   8.15472682850   8.15472682850
> MK> K_POINTS {automatic}
> MK> 1  1  1  0  0  0
> MK>               mixing_beta = 0.6 ,
> MK>
> MK>
=====================================================================
> MK> 2. With the files created in temp2/ directory from the above run,
MK>                         input file for pp.x
> MK>  &inputpp
> MK>     prefix  = 'H2'
> MK>     outdir =
> MK> '/export/mousumi/PWSCF_2.0.1/H2/PostProcess/dipole_mom/tmp2//' MK>
  filplot = 'H2_chdens2'
> MK>     plot_num = 0
> MK>  /
> MK>
> MK>
> =======================================================================
MK> 3. With the 'H2_chdens2' file created in the above run, file for MK>
                                 running chdens.x
> MK> &input
> MK>     nfile = 1
> MK>     filepp(1)='H2_chdens2'
> MK>     iflag = 3
> MK>     plot_out = 1
> MK>     idpol = 1
> MK>     output_format = 5
> MK> /
> MK>
> MK>
> =========================================================================
MK>
> MK>
> MK> _______________________________________________
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> MK>
> MK>
>
> --
>
> =======================================================================
Dr. Axel Kohlmeyer   e-mail: axel.kohlmeyer at theochem.ruhr-uni-bochum.de
Lehrstuhl fuer Theoretische Chemie          Phone: ++49 (0)234/32-26673
Ruhr-Universitaet Bochum - NC 03/53         Fax:   ++49 (0)234/32-14045
D-44780 Bochum  http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/
======================================================================= If
you make something idiot-proof, the universe creates a better idiot.
>
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