[Pw_forum] problem with ibrav = -12

[jose manuel menendez montes]

Dear All,

Has anyone used the new setting for the P monoclinic Bravais lattice
(ibrav=-12)? 

Using 4.3.2 version or the svn latest one everything goes smooth but
when it comes to analyse the crystal vectors, it turns out to work out a
completely different thing from what it is said in the manual
(INPUT_PW.html).

The relevant part of the output is pasted below:

     celldm(1)=   7.982458  celldm(2)=   1.638821  celldm(3)=   1.861446
     celldm(4)=   0.000000  celldm(5)=  -0.167251  celldm(6)=   0.000000

     crystal axes: (cart. coord. in units of alat)
               a(1) = (   1.000000   0.000000   0.000000 )  
               a(2) = (   0.000000   1.638821   0.000000 )  
               a(3) = (  -0.311328   0.000000   1.835226 )  

According to the manual: "Alternate choice (ibrav=-12) uses b as unique
axis: v1 = (a,0,0), v2 = (0,b,0), v3 = (a*sin(beta),0,c*cos(beta))
where beta is the angle between axis a and c". That is, a and b are
correct but c is not. Instead of (a*sin(beta),0,c*cos(beta)), we are
geting (c*cos(beta),0,c*sin(beta)).

Am I doing anything wrong? 

Any help would be very much appreciated.

------------------------------------------------------------------------

J.M. Menendez
Universidad de Oviedo (Spain)
Departamento de Quimica Fisica y Analitica
http://www.malta-consolider.com