[Pw_forum] program modification of virtual.f90

[Stefano Baroni]

Dear Yukihiro: many thanks for your interest i PWscf and Quenatum  
ESPRESSO. Some of the people that may address your query are likely  
not available during the next few days. I wish your question will be  
answered soon. Cheers - SB

On Mar 21, 2008, at 8:54 AM, yukihiro_okuno at fujifilm.co.jp wrote:

>
> Dear PW users and developer.
>
> I now want to use virtual crystal approximation for USPP.
>
> The virtual.f90 is not implemented still on the case
>
> that riiners is different (  where riiner is the length of pseudized
> argumentation function  and
>
> if r < rinner Q function is given like   Q_{n,m}(r) = r^{L} * (C1 +  
> C2r^{2}
> + C3r^{4} + .... ),
>
> The virtual.x output error  message like
>
>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
> %%%%%%%%%
>     from Virtual : error #         1
>     different rinner are not implemented (yet)
>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
> %%%%%%%%%
>
>
> So I want to modify the virtual.f90  in order to use  for the case  
> that
> ultra soft pseudo potentials
>
> have different rinner.
>
> If atom A and B had different different riiner r_A, r_B respectively (
> which lengths specify the pusedized lengths of
>
> charge argumentation function Q_{n,m}(r),  if r < riiner,  Q is  
> expressed
> like  polynomial;  Q_{n,m}(r) = r^{L} * (C1 + C2r^{2} + C3r^{4} + ....
>
> and r > riiner Q{n,m}(r) = qfun(r)   where qfun is defined in the  
> UPF file
> format.)
>
>
> ( we follow the paper PRB vol47  10142)
>
> The modification of virtual.f90  when A atom and B atom is mixed by  
> the
> ratio  A:B= x:1-x ,  I planed  the modification like ,
>
> 1)    We set new riiner = min(r_{A}.r_{B})    for each angular  
> momentum L
> for the virtual atom.
>
> 2)   then  we make virtual potential like
>
>    r < min(r_{A}. r_{B}) = r_{A}  = r_inner     ( we set r_{A} <  
> r_{B} )
>
>    upf_qfcoef(n,m) = x * qfcoef_{A}      (where  n, m is for A atom  
> index
> and qfcoef is A atom pseudized polynomial  coefficient C1,C2....)
>
>   upf_qfcoef(n,m)  = (1-x) * qfcoef_{B} (where  n,m is for B atom  
> index
> and qfcoef is B atom pseudized  polynomial coefficient )
>
>    r_{A} < r < r_{B}
>
>   qfun(n,m)[r}  = x * r^{L} * (C1_{A} + C2_{A} * r^{2} + C3_{A} *  
> r^{4} +
> ...)
>
>   qfun(n,m)[r] = (1-x) * qfun_{B}    ( where qfun is the argumentation
> function for r > riiner which are specified in UPF file ).
>
>    r_{B} < r
>
>    qfun(n,m)[r}  = x * qfun_{A}
>
>   qfun(n,m)[r] = (1-x) * qfun_{B}
>
>
> Is it right the above mentioned plan I wrote in order to modify the
> virtual.f90 ?
>
>
> Sincerely,
>
>
> Yukihiro Okuno.
>
>
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> Pw_forum at pwscf.org
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
[+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)

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