ABINIT Discussion Forums

Hi all members,

i'm using calculation of elastic constants for ternary material of Zinc blend structure, in input file i used:


the calculation stopped and show me this error:

--- !ERROR
message: |
In a non-metallic case (occopt<3), for a RF calculation,
if the eigenvalues are degenerate, the occupation numbers must also be degenerate.
However, the following pair of states gave :
k -state, band number 8, occ= 2.000000E+00eigenvalue= -5.304725E-02,
kq-state, band number 9, occ= 7.500000E-01, eigenvalue= -5.304725E-02.
Action : change occopt, consistently, in GS and RF calculations.
src_file: occeig.F90
src_line: 117
...

after, i restard the same calculation and changed occopt 3 by using LDA
the calculation completed and i find results :

Rigid-atom elastic tensor , in cartesian coordinates,
j1 j2 matrix element
dir pert dir pert real part imaginary part

1 5 1 5 0.0173180338 0.0000000000
1 5 2 5 -0.0025196114 0.0000000000
1 5 3 5 -0.0025191941 0.0000000000
1 5 1 6 -0.0000000002 0.0000000000
1 5 2 6 0.0000000007 0.0000000000
1 5 3 6 0.0000000002 0.0000000000

2 5 1 5 -0.0025191170 0.0000000000
2 5 2 5 0.0173300200 0.0000000000
2 5 3 5 -0.0025191939 0.0000000000
2 5 1 6 0.0000000000 0.0000000000
2 5 2 6 0.0000000007 0.0000000000
2 5 3 6 0.0000000002 0.0000000000

3 5 1 5 -0.0025191167 0.0000000000
3 5 2 5 -0.0025196110 0.0000000000
3 5 3 5 0.0173218120 0.0000000000
3 5 1 6 0.0000000000 0.0000000000
3 5 2 6 0.0000000007 0.0000000000
3 5 3 6 0.0000000000 0.0000000000

1 6 1 5 -0.0000000000 0.0000000000
1 6 2 5 -0.0000000000 0.0000000000
1 6 3 5 -0.0000000000 0.0000000000
1 6 1 6 0.0103930714 0.0000000000
1 6 2 6 0.0000000000 0.0000000000
1 6 3 6 -0.0000000000 0.0000000000

2 6 1 5 -0.0000000000 0.0000000000
2 6 2 5 0.0000000000 0.0000000000
2 6 3 5 0.0000000000 0.0000000000
2 6 1 6 0.0000000000 0.0000000000
2 6 2 6 0.0103805301 0.0000000000
2 6 3 6 -0.0000000000 0.0000000000

3 6 1 5 0.0000000000 0.0000000000
3 6 2 5 0.0000000000 0.0000000000
3 6 3 5 0.0000000000 0.0000000000
3 6 1 6 -0.0000000000 0.0000000000
3 6 2 6 -0.0000000000 0.0000000000
3 6 3 6 0.0103888474 0.0000000000

finally i get elastic constants:

Elastic Tensor (clamped ion) (unit:10^2GP):

5.0951406 -0.7412951 -0.7411724 -0.0000000 0.0000002 0.0000001
-0.7411497 5.0986670 -0.7411723 0.0000000 0.0000002 0.0000001
-0.7411496 -0.7412950 5.0962522 0.0000000 0.0000002 0.0000000
-0.0000000 -0.0000000 -0.0000000 3.0577467 0.0000000 -0.0000000
-0.0000000 0.0000000 0.0000000 0.0000000 3.0540569 -0.0000000
0.0000000 0.0000000 0.0000000 -0.0000000 -0.0000000 3.0565039

Elastic Tensor (relaxed ion) (unit:10^2GP):
(at fixed electric field boundary condition)

5.0951406 -0.7412951 -0.7411724 -0.0000000 0.0000002 0.0000001
-0.7411497 5.0986670 -0.7411723 -0.0000000 0.0000002 0.0000001
-0.7411496 -0.7412950 5.0962522 0.0000000 0.0000002 0.0000000
-0.0000000 -0.0000000 0.0000000 3.0434104 0.0000000 0.0000000
-0.0000000 0.0000000 0.0000000 0.0000000 3.0396484 -0.0000000
-0.0000000 0.0000000 0.0000000 0.0000000 -0.0000000 3.0421411

so my question is it this results logic, if not how i resolve it ?

thanks all

kind regards

Hocine