[Pw_forum] ibrav for orthorhombic space group

[xirainbow]

Dear David Foster:
          Orthorhombic P = composed of P.
          Orthorhombic base-centered(bco) = C and A.
          Orthorhombic face-centered = F
          Orthorhombic body-centered  = I.
          You can find more information at here if you can read Chinese.
http://blog.sina.com.cn/s/blog_5f15ead20100wmjl.html


On Fri, Jan 10, 2014 at 2:41 PM, David Foster <davidfoster751 at yahoo.com> wrote:
> Hi everybody
>
> Orthorhombic space group (Numbered from 16 to 74) has five different kinds of classes starting
>
> with "P" "C"  "A"  "F"  "I".
>
> P such as 56.Pccn        or  57.Pbcm
>
> C such as 36.Cmc21  or   37.Ccc2
>
> A such as 40.Ama2   or    41.Aba2
>
> F such as 42.Fmm2           or     43.Fdd2
>
> I such as 44.Imm2          or    45.Iba2
>
> My question is about ibrav assignment to above space groups.
>
>
> in manual we have:
>
> ========================
>  8          Orthorhombic P                  celldm(2)=b/a
>                                              celldm(3)=c/a
>       v1 = (a,0,0),  v2 = (0,b,0), v3 = (0,0,c)
>
>   9          Orthorhombic base-centered(bco) celldm(2)=b/a
>                                              celldm(3)=c/a
>       v1 = (a/2, b/2,0),  v2 = (-a/2,b/2,0),  v3 = (0,0,c)
>  -9          as 9, alternate description
>       v1 = (a/2,-b/2,0),  v2 = (a/2,-b/2,0),  v3 = (0,0,c)
>
>  10          Orthorhombic face-centered      celldm(2)=b/a
>                                              celldm(3)=c/a
>       v1 = (a/2,0,c/2),  v2 = (a/2,b/2,0),  v3 = (0,b/2,c/2)
>
>  11          Orthorhombic body-centered      celldm(2)=b/a
>                                              celldm(3)=c/a
>       v1=(a/2,b/2,c/2),  v2=(-a/2,b/2,c/2),  v3=(-a/2,-b/2,c/2)
> ===========================
>
> so, it is clear that ibrav for "P" is 8, for "I" is 11 (I am not sure), for "F" is 10.
>
> What about "C" and "A"?
>
>
>
>
> Regards
>
> David Foster
>
> Ph.D. Student of Chemistry
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum



-- 
____________________________________
Hui Wang
School of physics, Henan University of Science and Technology, Henan, China