ABINIT Discussion Forums

what it is the vector primitive of the monoclinical structure?

One way of defining a monoclinic cell is to use
with no rprim.

hello,
I try to study the properties of TlGaSe2, it crystallizes in the monoclinic structure with base centred ( space group 15)
I created an input file, but the problem is that as I SPGroup 15 but it shows me this error error [ Largest error (above) is so large (0.01) that either input atomic coordinates (xred)
are wrong or space group symmetry data is wrong.
Action : correct your input file.], and when I comente SPGroup it crystallizes in the triclinic default structure.

this is my input files


chkprim 0
#Definition of the k-point grids
kptopt 1

nshiftk 4
shiftk 0.5 0.5 0.5
0.5 0.0 0.0
0.0 0.5 0.0
0.0 0.0 0.5


ngkpt 6 6 6


getwfk -1



#Definition of the unit cell
acell 10.8797 10.7975 15.7070
angdeg 90.0 100.47 90.0
spgroup 15

#Definition of the atom types
ntypat 3
znucl 81 31 34





#Definition of the atoms
natom 9
typat 1 1 2 2 3 3 3 3 3
xred 0.4632 0.1642 0.1078
0.2163 0.0487 0.6158
0.3876 0.1965 0.8378
0.1461 0.0639 0.3391
0.0000 0.9295 0.2500
0.0000 0.4468 0.2500
0.2047 0.4370 0.0695
0.2588 0.1882 0.2508
0.4541 0.3124 0.5732

#Definition of the planewave basis set
ecut 40.0

#Definition of the SCF procedure
nstep 10
toldfe 1.0d-6


diemac 12.0


# add to conserve old < 6.7.2 behavior for calculating forces at each SCF step
optforces 1

thank you in advance.

It might mean that you xred coordinate do not respect the symmetries of the space group.
That's probably true since abinit does not fine the correct space group when you don't specify it.
I think that if you just give the assymetric positions, abinit will reconstruct the symmetric ones with respect to the symmetries of the spgroup

Jordan