# [Pw_forum] Structural properties

Éric Germaneau germaneau at gucas.ac.cn
Fri Nov 4 16:43:14 CET 2011

```Dear Yun Song,

I'm sorry but that does not seem to right.
If H is the cell description in Cartesian coordinates, meaning H =
CELL_PARAMETERS * alat, we have :

V1(1) = H(1,1)
V1(2) = H(2,1)
V1(3) = H(3,1)

V2(1) = H(1,2)
V2(2) = H(2,2)
V2(3) = H(3,2)

V3(1) = H(1,3)
V3(2) = H(2,3)
V3(3) = H(3,3)

a = sqrt(dot_product(V1,V1))
b = sqrt(dot_product(V2,V2))
c = sqrt(dot_product(V3,V3))

alpha = acos( dot_product(V2,V3) / ( b * c ) ) /  RAD
beta  = acos( dot_product(V1,V3) / ( c * a ) ) /  RAD
gamma = acos( dot_product(V1,V2) / ( a * b ) ) /  RAD

Best,

Éric.

On 11/03/2011 11:02 PM, KangYun Song wrote:
> Dear Nicola:
>         The lattice parameter from output is:
>
> CELL_PARAMETERS (alat=5.07500000)
> 1.0004582120.0000000000.000000000
> -0.5002291060.8664222270.000000000
> 0.0000000000.0000000001.636876279
>
> It means
>
>    acosx/5.075   acosy/5.075   acosz/5.075
>
>    bcosx/5.075   bcosy/5.075   bcosz/5.075
>
>    cosx/5.075    ccosy/5.075   ccosz/5.075
>
> Last example is:
>
>    a=1.000458212*5.075,
>
>    c=1.636876279*5.075
>
> Yun Song,Kang
> Department Physical Science and Technology of  Inner Mongolia University.
>
> ------------------------------------------------------------------------
> Date: Tue, 1 Nov 2011 10:19:55 -0200
> From: arvifis at gmail.com
> To: pw_forum at pwscf.org
> Subject: Re: [Pw_forum] Structural properties
>
> Dear Nicolar, what kind of calculate are you doing..?? relax or
> vc-relax ..??
>
>
> PhD std Arles V. Gil Rebaza
> IFLP - Argentina
>
> 2011/11/1 nicolas bruno <nbruno014 at gmail.com <mailto:nbruno014 at gmail.com>>
>
>     Dear all,
>
>     I am a new user of  QE and I want to calculate the structural
>     properties for AlN, could someone direct me for this in particular how
>     interpret the output to get the lattice parameter?
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> --
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Dr. Éric Germaneau

College of Physical Sciences