[Pw_forum] About: the system is metallic, specify occupations?

Rahmat Gunawan s305igun at mail.chem.itb.ac.id
Wed Nov 22 10:17:42 CET 2006


Dear PW_Forum

Thanks to Stefano

it is good for me. I try your suggestion to build my input

Thanks again

Sincerely Yours

Rahmat Gunawan



> A system with an even number of electron per unit cell is an isulator or
> a metal
> according to whether or not these electrons (doubly) occupy completely a
> set of  bands
> separated from the subsequent ones by an energy gap.
> A system with an odd number of particles can't possibly do that (if it
> is not magnetic).
> In PWscf when dealing with a metal or a magnetic system you need to
> specify how
> to describe partial occupation of energy bands.
> Relevant input variables are: occupation, smearing, degauss in the
> system namelist
> best,
>    stefano
>
> PS: please note that in crystal coordinates
>
>     H      0.000000000    0.000000000    3.250000000
>
> is equivalent to
>
>     H      0.000000000    0.000000000    0.250000000
>
> is this what you want ???
>
>
>
> Rahmat Gunawan wrote:
>
>>Dear PW_Forum...
>>
>>I have tried some examples to know how graphite system can learned in
>>PWscf. I read some article in journals: J.Phys.Chem. B., 2006, 110, 14832
>>and J.Chem.Phys., 118(3), 1003. I have problem about input, now I consult
>>to PW_Forum my interaction bond input of "graphite---H"
>>
>>&CONTROL
>>                 calculation = 'scf' ,
>>                restart_mode = 'from_scratch' ,
>>                      outdir = '/home/s3/s305igun/tmp/' ,
>>                  pseudo_dir = '/home/s3/s305igun/pseudo/' ,
>>                      prefix = 'C' ,
>>                     tstress = .true. ,
>>                     tprnfor = .true. ,
>> /
>> &SYSTEM
>>                       ibrav = 4,
>>                   celldm(1) = 4.64117,
>>                   celldm(3) = 2.7264,
>>                         nat = 5,
>>                        ntyp = 2,
>>                     ecutwfc = 25.0 ,
>>                     ecutrho = 100.0 ,
>> /
>> &ELECTRONS
>> /
>>ATOMIC_SPECIES
>>    H    1.00794  H.vbc.UPF
>>    C   12.01100  C.pz-vbc.UPF
>>ATOMIC_POSITIONS crystal
>>    H      0.000000000    0.000000000    3.250000000
>>    C      0.000000000    0.000000000    0.000000000
>>    C      0.333333333    0.666666666    0.000000000
>>    C      0.000000000    0.000000000    0.500000000
>>K_POINTS
>>  10
>>   0.1250000  0.1250000  0.1250000   1.00
>>   0.1250000  0.1250000  0.3750000   3.00
>>   0.1250000  0.1250000  0.6250000   3.00
>>   0.1250000  0.1250000  0.8750000   3.00
>>   0.1250000  0.3750000  0.3750000   3.00
>>   0.1250000  0.3750000  0.6250000   6.00
>>   0.1250000  0.3750000  0.8750000   6.00
>>   0.1250000  0.6250000  0.6250000   3.00
>>   0.3750000  0.3750000  0.3750000   1.00
>>   0.3750000  0.3750000  0.6250000   3.00
>>
>>I need your help, is it true input? because at output file write: "the
>>system is metallic, specify occupations?" I do not understand about this
>>statements.
>>
>>Thanks very much, succes for your research
>>
>>Sincerely yours.
>>
>>Rahmat gunawan
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>>
>>
>
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