Matrix inversion failed in EEM/QEq

GULP
1

I am trying to compute partial charges of a cubic CdS crystal using GULP. I am getting the warnings followed by an errors:
WARNING : The irreducible atom 2 is equivalent to atom 1
WARNING : The irreducible atom 3 is equivalent to atom 1
WARNING : The irreducible atom 4 is equivalent to atom 1
WARNING : The irreducible atom 6 is equivalent to atom 2
…
ERROR : matrix inversion failed in EEM/QEq

I shall be highly obliged if someone tells me the remedy to solve that.
My input file

efg pot eem bond
cell
5.89 5.89 5.89 90 90 90
fractional 8
Cd 0 0 0
Cd 0 0.5 0.5
Cd 0.5 0 0.5
Cd 0.5 0.5 0
S 0.25 0.25 0.25
S 0.75 0.75 0.25
S 0.75 0.25 0.75
S 0.25 0.75 0.75
space
216

Thank you…

2

If you use space group symmetry you only need to provide the asymmetric unit, not the full set of coordinates for the whole cell, otherwise the symmetry-generated atoms will duplicate those that you’ve already input.

1 Like
3

Sir I followed your suggestion and tried, but this error keeps on popping up. This time I have taken the coordinates of Cd and S of asymmetric points from .cif file.

efg pot eem bond
cell
5.818 5.818 5.818 90.000 90.000 90.000
fractional
Cd 0.00000 0.00000 0.00000
S 0.25000 0.25000 0.25000
space
F -4 3 m

!! ERROR : matrix inversion failed in EEM/QEq

Now, the warnings are not appearing. Only this matrix inversion error is popping up. I am attaching the cif file I am using as well.

data_global
chemical_name_mineral ‘Hawleyite’
loop
_publ_author_name
‘Traill R J’
‘Boyle R W’
_journal_name_full ‘American Mineralogist’
_journal_volume 40
_journal_year 1955
_journal_page_first 555
_journal_page_last 559
_publ_section_title
;
Hawleyite, isometric cadmium sulphide, a new mineral
;
_database_code_amcsd 0000070
_chemical_formula_sum ‘Cd S’
_cell_length_a 5.818
_cell_length_b 5.818
_cell_length_c 5.818
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 196.934
_exptl_crystal_density_diffrn 4.873
symmetry_space_group_name_H-M ‘F -4 3 m’
loop
space_group_symop_operation_xyz
‘x,y,z’
‘x,1/2+y,1/2+z’
‘1/2+x,y,1/2+z’
‘1/2+x,1/2+y,z’
‘-z,x,-y’
‘-z,1/2+x,1/2-y’
‘1/2-z,x,1/2-y’
‘1/2-z,1/2+x,-y’
‘-y,z,-x’
‘-y,1/2+z,1/2-x’
‘1/2-y,z,1/2-x’
‘1/2-y,1/2+z,-x’
‘-x,y,-z’
‘-x,1/2+y,1/2-z’
‘1/2-x,y,1/2-z’
‘1/2-x,1/2+y,-z’
‘x,-z,-y’
‘x,1/2-z,1/2-y’
‘1/2+x,-z,1/2-y’
‘1/2+x,1/2-z,-y’
‘z,-y,-x’
‘z,1/2-y,1/2-x’
‘1/2+z,-y,1/2-x’
‘1/2+z,1/2-y,-x’
‘y,-x,-z’
‘y,1/2-x,1/2-z’
‘1/2+y,-x,1/2-z’
‘1/2+y,1/2-x,-z’
‘x,z,y’
‘x,1/2+z,1/2+y’
‘1/2+x,z,1/2+y’
‘1/2+x,1/2+z,y’
‘z,y,x’
‘z,1/2+y,1/2+x’
‘1/2+z,y,1/2+x’
‘1/2+z,1/2+y,x’
‘y,x,z’
‘y,1/2+x,1/2+z’
‘1/2+y,x,1/2+z’
‘1/2+y,1/2+x,z’
‘-z,-x,y’
‘-z,1/2-x,1/2+y’
‘1/2-z,-x,1/2+y’
‘1/2-z,1/2-x,y’
‘-y,-z,x’
‘-y,1/2-z,1/2+x’
‘1/2-y,-z,1/2+x’
‘1/2-y,1/2-z,x’
‘-x,-y,z’
‘-x,1/2-y,1/2+z’
‘1/2-x,-y,1/2+z’
‘1/2-x,1/2-y,z’
‘z,-x,-y’
‘z,1/2-x,1/2-y’
‘1/2+z,-x,1/2-y’
‘1/2+z,1/2-x,-y’
‘y,-z,-x’
‘y,1/2-z,1/2-x’
‘1/2+y,-z,1/2-x’
‘1/2+y,1/2-z,-x’
‘x,-y,-z’
‘x,1/2-y,1/2-z’
‘1/2+x,-y,1/2-z’
‘1/2+x,1/2-y,-z’
‘-x,z,-y’
‘-x,1/2+z,1/2-y’
‘1/2-x,z,1/2-y’
‘1/2-x,1/2+z,-y’
‘-z,y,-x’
‘-z,1/2+y,1/2-x’
‘1/2-z,y,1/2-x’
‘1/2-z,1/2+y,-x’
‘-y,x,-z’
‘-y,1/2+x,1/2-z’
‘1/2-y,x,1/2-z’
‘1/2-y,1/2+x,-z’
‘-x,-z,y’
‘-x,1/2-z,1/2+y’
‘1/2-x,-z,1/2+y’
‘1/2-x,1/2-z,y’
‘-z,-y,x’
‘-z,1/2-y,1/2+x’
‘1/2-z,-y,1/2+x’
‘1/2-z,1/2-y,x’
‘-y,-x,z’
‘-y,1/2-x,1/2+z’
‘1/2-y,-x,1/2+z’
‘1/2-y,1/2-x,z’
‘z,x,y’
‘z,1/2+x,1/2+y’
‘1/2+z,x,1/2+y’
‘1/2+z,1/2+x,y’
‘y,z,x’
‘y,1/2+z,1/2+x’
‘1/2+y,z,1/2+x’
‘1/2+y,1/2+z,x’
loop
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Cd 0.00000 0.00000 0.00000
S 0.25000 0.25000 0.25000

4

Did you read the documentation for the eem keyword in the help text that says:

“Only available for H, C, N, O, F, Si, Al and P”

The error is therefore likely to be because you didn’t input any parameters for Cd and S & so you have a null matrix.

1 Like
5

Yes sir, I got it now…
Thank you very much…

I have tried with qeq after reading the documentation, it’s running fine.