-    PROUSTITE     -    Ag3AsS3

 

Crystal Structure 


Because of the translational symmetry all the calculations are performed in the primitive unit cell and not in the conventional unit cell. The following information regarding the structure is given with respect to this primitive unit cell, which sometimes can take an unintuitive shape.

Symmetry (experimental): 

Space group:  161  R3c 
Lattice parameters (Å):  10.7680  10.7680  8.7200 
Angles (°):  90  90  120 

Symmetry (theoretical): 

Space group:  161  R3c 
Lattice parameters (Å):  6.8094  6.8094  6.8094 
Angles (°):  101.91  101.91  101.91 

Cell contents: 

Number of atoms:  14 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Ag:  0.4677  0.2442  0.9188 
As:  0.0083  0.0083  0.0083 
S:  0.5994  0.2637  0.2843 
Ag:  0.2442  0.9188  0.4677 
S:  0.2637  0.2843  0.5994 
Ag:  0.4188  0.7442  0.9677 
As:  0.5083  0.5083  0.5083 
S:  0.7843  0.7637  0.0994 
Ag:  0.9188  0.4677  0.2442 
S:  0.2843  0.5994  0.2637 
Ag:  0.7442  0.9677  0.4188 
S:  0.7637  0.0994  0.7843 
Ag:  0.9677  0.4188  0.7442 
S:  0.0994  0.7843  0.7637 
Atom type 

We have listed here the reduced coordinates of all the atoms in the primitive unit cell.
It is enough to know only the position of the atoms from the assymetrical unit cell and then use the symmetry to build the whole crystal structure.

Visualization of the crystal structure: 

Size:

Nx:  Ny:  Nz: 
You can define the size of the supercell to be displayed in the jmol panel as integer translations along the three crys­tallo­gra­phic axis.
Please note that the structure is represented using the pri­mi­tive cell, and not the conventional one.
 

Dielectric Properties 


We define:

  • The Born effective charges, also called dynamical charges, are tensors that correspond to the energy derivative with respect to atomic displacements and electric fields or, equivalently, to the change in atomic force due to an electric field: The sum of the Born effective charges of all nuclei in one cell must vanish, element by element, along each of the three directions of the space.
  • The dielectric tensors are the energy derivative with respect to two electric fields. They also relate the induced polarization to the external electric field.

Born effective charges (Z): 

Ag: 1.0845 0.1107 0.1816 
0.1660 0.7204 -0.1101 
-0.0854 -0.2192 0.8278 
Eig. Value: 1.1314 0.5629 0.9385 
As: 2.5318 0.2072 -0.0000 
-0.2072 2.5318 0.0000 
0.0000 -0.0000 0.9832 
Eig. Value: 2.5318 2.5318 0.9832 
S: -2.1673 -0.5013 0.6319 
-0.5254 -1.3255 0.3599 
0.2058 0.3562 -1.1556 
Eig. Value: -2.6070 -1.1691 -0.8723 
Ag: 0.6916 0.0608 -0.1861 
0.1162 1.1133 -0.1022 
-0.1471 0.1836 0.8278 
Eig. Value: 0.5629 1.1314 0.9385 
S: -1.0914 -0.0958 -0.0042 
-0.1199 -2.4014 -0.7272 
0.2056 -0.3564 -1.1556 
Eig. Value: -1.1691 -2.6070 -0.8723 
Ag: 0.6916 -0.0608 0.1861 
-0.1162 1.1133 -0.1022 
0.1471 0.1836 0.8278 
Eig. Value: 0.5629 1.1314 0.9385 
As: 2.5318 -0.2072 -0.0000 
0.2072 2.5318 0.0000 
0.0000 -0.0000 0.9832 
Eig. Value: 2.5318 2.5318 0.9832 
S: -1.0914 0.0958 0.0042 
0.1199 -2.4014 -0.7272 
-0.2056 -0.3564 -1.1556 
Eig. Value: -1.1691 -2.6070 -0.8723 
Ag: 0.9313 -0.2545 0.0045 
-0.1992 0.8737 0.2123 
0.2326 0.0356 0.8278 
Eig. Value: 1.1314 0.5629 0.9385 
S: -1.9805 0.6332 -0.6277 
0.6092 -1.5123 0.3673 
-0.4114 0.0001 -1.1556 
Eig. Value: -2.6070 -1.1691 -0.8723 
Ag: 1.0845 -0.1107 -0.1816 
-0.1660 0.7204 -0.1101 
0.0854 -0.2192 0.8278 
Eig. Value: 1.1314 0.5629 0.9385 
S: -2.1673 0.5013 -0.6319 
0.5254 -1.3255 0.3599 
-0.2058 0.3562 -1.1556 
Eig. Value: -2.6070 -1.1691 -0.8723 
Ag: 0.9313 0.2545 -0.0045 
0.1992 0.8737 0.2123 
-0.2326 0.0356 0.8278 
Eig. Value: 1.1314 0.5629 0.9385 
S: -1.9805 -0.6332 0.6277 
-0.6092 -1.5123 0.3673 
0.4114 0.0001 -1.1556 
Eig. Value: -2.6070 -1.1691 -0.8723 
Atom type 

Dielectric tensors: 

 
Ɛ10.4181 0.0000 0.0000 
-0.0000 10.4181 0.0000 
0.0000 0.0000 8.5396 
Eig. Value: 10.4181 10.4181 8.5396 
Refractive index (N): 3.2277 0.0000 0.0000 
-0.0000 3.2277 0.0000 
0.0000 0.0000 2.9223 
Eig. Value: 3.2277 3.2277 2.9223 
Ɛ00.0000 0.0000 0.0000 
0.0000 0.0000 0.0000 
0.0000 0.0000 0.0000 
Eig. Value: 0.0000 0.0000 0.0000