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<DIV><FONT size=2 face=Arial>You just need to pick up a math textbook of high
school. </FONT></DIV>
<DIV><FONT size=2 face=Arial>Given a vector a = (ax, ay, az), |a| =
sqrt(ax^2+ay^2+az^2).</FONT></DIV>
<DIV><FONT size=2 face=Arial>For the angle between two vectors, you need to know
their dot product,</FONT></DIV>
<DIV><FONT size=2 face=Arial>cos(angle) = a dot b /(|a||b|), where a dot b =
ax*bx + ay*by + az*bz.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Hope you know which two lattice vectors correspond
to which angle.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>zhou huiqun</FONT></DIV>
<DIV><FONT size=2 face=Arial>@earth sciences, nanjing university,
china</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=konda.physics@gmail.com
href="mailto:konda.physics@gmail.com">Kondaiah Samudrala</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=pw_forum@pwscf.org
href="mailto:pw_forum@pwscf.org">pw_forum@pwscf.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Sunday, January 29, 2012 4:31
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [Pw_forum] Requesting for
structural details</DIV>
<DIV><BR></DIV>Dear All,<BR><BR>I am working on layered type material which
crystallizes in rhombohedral structure with space group 166 ( ibrav =5). In
the i/p file for VC-Relax, i used the lattice parameters and angle as
celldm(1)=7.4870 and celldm(4)=0.586005.<BR><BR>In the first step of the of
the o/p file shows the basis vectors as <BR>0.454970 -0.262677
0.850884<BR>0.000000 0.525354 0.850884<BR>-0.4504970 -0.262677
0.850884<BR><BR>After completing the VC-Relax i got the basis vectors
as<BR><BR><BR>CELL-PARAMETERS ( alat=7.4870)<BR>0.441119855 -0.254680667
0.78874941<BR>0.00000000 0.509361335 0.78874941<BR>-0.441119855
-0.254680667 0.78874941<BR><BR> with this o/p values, how can i
calculate lattice vector and angle for my material ( For orthorhombic and
tetragonal structures i calculated lattice parametrs successfully but i am not
able to do this structure ).<BR><BR><BR>i am requesting your favorable
reply.<BR><BR>with regards<BR>S.Appalakondaiah<BR>PhD Scholar<BR>University of
Hyderabad<BR>Hyderabad<BR>India<BR><BR><BR><BR><BR>
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