[Pw_forum] Electron-phonon interaction ...

[Malgorzata Wierzbowska]

On Tue, 19 Dec 2006, Amit Kumar wrote:

>>    Dear Malgorzata,
>
>
>      I have not recieved your reply yet.
>      Have you checked your sample Mg-script???
>      It's working fine for your celldm(3) = 3.21 but giving the error
>      even for celldm(3) = 4.21. I'm confused. I think it's not
>      expected. Right????
>

        I have checked that it is working with celldm(3) = 8.12 which is
        5*1.624 (1.624 is c/a ratio in Mg hexagonal).


>      Waiting for your suggestions.
>

        You need to change atomic positions in z-direction if you change
        c/a (if "normally", with c/a=1.624 you have 0.25 and 0.75, then
        for celldm(3)=5*hex, if you want 2 layer slab in the middle of
        the cell, you put   0.25 --> 0.5-0.25/5=0.45 and
        0.75 --> 0.5+0.25/5=0.55

    Here are mine:

  &system
     ibrav=  4, celldm(1) = 6.06, celldm(3)= 8.12,
     ..............


ATOMIC_SPECIES
  Mg  24.3  Mg.pz-n-vbc.UPF
ATOMIC_POSITIONS {crystal}
  Mg   0.333333333   0.666666666  0.45
  Mg   0.666666666   0.333333333  0.55
K_POINTS....................................

    There is no error!
    Gosia




>      Regards,
>      Amit
>
>
>  It' s very nice to recieve your amiable reply.
>>    I told you that the error was due to some other reason not due to
>>    k-point grid I have used.
>>    Yes!!!!!!!!!! I have found out the reason.
>>    It's due to  celldm(3)  (= 16.0 ) I have used.
>>    If I use small celldm(3) like you, then I'm also not getting any error.
>> 
>>    But I'm little confused. To study 2D case properly,  we should use a
>> large c/a ratio.
>>    Right????????? Then why a big ratio showing some different  error like
>>    "can't remap k-point grid".
>>    Thank you very much for your kind help.
>> 
>>    Regards,
>>    Amit
>> 
>> 
>> 
>