-    SMITHSONITE     -    ZnCO3

The crystal structure is fully relaxed (both unit cell parameters and atomic positions under symmetry constraints) starting from an experimental structure similar to the one reported in AMCSD 

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:  167  R-3c 
Lattice parameters (Å):  4.6528  4.6528  15.0250 
Angles (°):  90.0  90.0  120.0 

Symmetry (theoretical): 

Space group:  167  R-3c 
Lattice parameters (Å):  5.5675  5.5675  5.5675 
Angles (°):  49.1  49.1  49.1 

Cell contents: 

Number of atoms:  10 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Zn:  0.0000  0.0000  0.0000 
C:  0.2500  0.2500  0.2500 
O:  0.5259  0.9741  0.2500 
O:  0.9741  0.2500  0.5259 
Zn:  0.5000  0.5000  0.5000 
C:  0.7500  0.7500  0.7500 
O:  0.7500  0.4741  0.0259 
O:  0.2500  0.5259  0.9741 
O:  0.4741  0.0259  0.7500 
O:  0.0259  0.7500  0.4741 
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.
     

Powder Raman 

Powder Raman spectrum

The intensity of the Raman peaks is computed within the density-functional perturbation theory. The intensity depends on the temperature (for now fixed at 300K), frequency of the input laser (for now fixed at 21834 cm-1, frequency of the phonon mode and the Raman tensor. The Raman tensor represents the derivative of the dielectric tensor during the atomic displacement that corresponds to the phonon vibration. The Raman tensor is related to the polarizability of a specific phonon mode.

Horizontal:
Xmin:
Xmax:
Vertical:
Ymin:
Ymax:
 
Choose the polarization of the lasers.
I ∥ 
I ⊥ 
I Total 

Data about the phonon modes

Frequency of the transverse (TO) and longitudinal (LO) phonon modes in the zone-center. The longitudinal modes are computed along the three cartesian directions. You can visualize the atomic displacement pattern corresponding to each phonon by clicking on the appropriate cell in the table below.

1
ac
0
0
0
0
2
ac
0
0
0
0
3
ac
0
0
0
0
4
A2u
148
148
148
168
5
Eu
168
168
168
168
6
Eu
168
169
169
198
7
Eu
198
198
198
198
8
Eu
198
207
207
207
9
Eg
207
207
207
207
6.084e+39
3.6
7.882e+39
4.7
1.397e+40
8.3
10
Eg
207
221
221
221
6.084e+39
3.6
5.243e+39
3.1
1.133e+40
6.8
11
A1u
221
233
233
231
12
A2g
296
296
296
296
13
Eu
300
300
300
300
14
Eu
300
307
307
300
15
Eg
307
307
307
307
2.070e+40
12.4
2.904e+40
17.3
4.974e+40
29.7
16
Eg
307
352
352
307
2.070e+40
12.4
2.532e+40
15.1
4.602e+40
27.5
17
A2u
352
367
367
395
18
A2g
418
418
418
418
19
Eg
720
720
720
720
3.820e+39
2.3
4.084e+39
2.4
7.904e+39
4.7
20
Eg
720
720
720
720
3.820e+39
2.3
3.618e+39
2.2
7.438e+39
4.4
21
Eu
734
734
734
734
22
Eu
734
737
737
734
23
A2u
830
830
830
840
24
A2g
840
840
840
851
25
A1u
1098
1098
1098
1098
26
A1g
1099
1099
1099
1099
1.642e+41
98.0
3.343e+39
2.0
1.675e+41
100.0
27
Eu
1412
1412
1412
1412
28
Eu
1412
1418
1418
1412
29
Eg
1418
1418
1418
1418
1.226e+40
7.3
2.065e+40
12.3
3.290e+40
19.6
30
Eg
1418
1574
1574
1418
1.226e+40
7.3
1.307e+40
7.8
2.533e+40
15.1
No.  Char.  ω TO  ω LOx  ω LOy  ω LOz  I ∥  I ⊥  I Total 
You can define the size of the supercell for the visualization of the vibration.
Nx: 
Ny: 
Nz: 
Normalized
Raw
Options for intensity.