Very thanks Regards David Foster
Ph.D. Student of Chemistry -------------------------------------------- On Fri, 1/10/14, xirainbow <nkxirainbow at gmail.com> wrote: Subject: Re: [Pw_forum] ibrav for orthorhombic space group To: "PWSCF Forum" <pw_forum at pwscf.org> Date: Friday, January 10, 2014, 6:42 AM 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 _______________________________________________ Pw_forum mailing list Pw_forum at pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
