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<DIV><FONT size=2 face=Arial>I'm afraid the formula for calculating cosA should
be</FONT></DIV>
<DIV><FONT size=2 face=Arial>cosA = b (*) c / (|b| | c|)</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>dr. zhou huiqun</FONT></DIV>
<DIV><FONT size=2 face=Arial>@earth sciences, nanjing university,
china</FONT></DIV>
<DIV> </DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=flux_ray12@163.com href="mailto:flux_ray12@163.com">GAO Zhe</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=pw_forum@pwscf.org
href="mailto:pw_forum@pwscf.org">PWSCF Forum</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, November 16, 2011 8:53
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [Pw_forum] calculation of
lattice parameter and angle of rhombohedral structure</DIV>
<DIV><BR></DIV>
<DIV
style="LINE-HEIGHT: 1.7; FONT-FAMILY: arial; COLOR: #000000; FONT-SIZE: 14px">the
three basis vectors of rhombohedral are (after relaxation) :<BR>a = (
0.636439417 -0.367448469 0.640642896 )<BR>b = (
0.000000000 0.734896938 0.640642896 )<BR>c = (
-0.636439417 -0.367448469 0.640642896 )<BR>then the lattice
paremeter should be: A = sqrt (a1^2+a2^2+a3^2) * alat = 8.05092296 a.u.
.<BR>The angle between two vectors can be calculated by:<BR>cosA = a (*) b /
|a (*) b|,<BR>where a and b are basis vectors, (*) represents the dot
product.<BR><BR>
<DIV>--<BR>GAO Zhe<BR>CMC Lab, MSE, SNU, Seoul, S.Korea<BR></DIV>
<DIV id=divNeteaseMailCard></DIV><BR>At 2011-11-16
20:14:38,"yedu kondalu" <nykondalu@gmail.com> wrote:<BR>
<BLOCKQUOTE
style="BORDER-LEFT: rgb(204,204,204) 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex"
id=isReplyContent>Dear users,<BR><BR> I did the
optimization for a compound using variable cell approximation using PWSCF,
which belongs to the space group R3m(160) Rhombohedral representation.
The primitive vectors in terms of lattice parameter a = 8.25791360
a.u.
<BR>
a(1) = ( 0.619505 -0.357671 0.698774 )
<BR>
a(2) = ( 0.000000 0.715343 0.698774
)
<BR>
a(3) = ( -0.619505 -0.357671 0.698774 )
<BR><BR>after completion of optimization step, the primitive
vectors<BR><BR>CELL_PARAMETERS (alat= 8.25791360)<BR>
0.636439417 -0.367448469 0.640642896<BR>
0.000000000 0.734896938 0.640642896<BR>
-0.636439417 -0.367448469 0.640642896<BR><BR>can u please
explain me <BR><BR>how can I calculate the lattice parameter <B>a</B> and
the <B>angle (alpha)</B> ???<BR><BR>Thanks in
advance<BR><BR>
Regards<BR>
Yedukondalu<BR><BR><BR></BLOCKQUOTE></DIV><BR><BR><SPAN
title=neteasefooter><SPAN id=netease_mail_footer></SPAN></SPAN>
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