[Pw_forum] Interpretation of vc-relax output

[Ridwan Agbaoye]

Good Morning Everybody,


 
I need some help withthe interpretation of vc-relax output and conversion from  alat to bohr

I want to do vc-relax calculation for a monoclinic system but i decide to start with silicon a face-centered cubic system to understand the concept of vc-relax properly I tried vc-relax forsilicon and i got the following output 

Begin Final Coordinate

New Unit Cell volume =276.90769au^3

CELLPARAMETERS(alat=10.60660172)

-0.487685488 -0.000000000  0.487685488

 0.000117363 0.487685488    0.487685488

-0.487685488 0.487685488  -0.000000000

ATOMICPOSITIONS(alat)

si   -0.035697193  -0.035697193  -0.035697193

si   0.208182292    0.208182292    0.208182292

Endof Final coordinate


 
Myinput file has 


 
ibrav=0   nat=2    ntyp=2


 
CELLPARAMETER cubic

-7.5000 0.0000  7.5000

0.0000 7.5000   7.5000

-7.5000 7.5000   0.0000


 
How exactly do we derive our celldm(1) and how do we convert to bohr


Do we need to convert the atomic position from alat to Bohr or Angstrom


must i use bohr as the unit of CELL PARAMETERS or i can use Angstrom and declare it as CELL PARAMETER(angstrom) 


Agbaoye Ridwan Olamide

Federal University of Agriculture, Abeokuta

M.Sc.(in view)

agbaoyeridwan at yahoo.com
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