-    OTAVITE     -    CdCO3

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):  4.9207  4.9207  16.2968 
Angles (°):  90.0  90.0  120.0 

Symmetry (theoretical): 

Space group:  167  R-3c 
Lattice parameters (Å):  6.0189  6.0189  6.0189 
Angles (°):  48.4  48.4  48.4 

Cell contents: 

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

Atomic positions (theoretical):

Cd:  0.0000  0.0000  0.0000 
C:  0.2500  0.2500  0.2500 
O:  0.5086  0.9914  0.2500 
O:  0.9914  0.2500  0.5086 
Cd:  0.5000  0.5000  0.5000 
C:  0.7500  0.7500  0.7500 
O:  0.7500  0.4914  0.0086 
O:  0.2500  0.5086  0.9914 
O:  0.4914  0.0086  0.7500 
O:  0.0086  0.7500  0.4914 
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
77
77
77
107
5
Eu
107
107
107
107
6
Eu
107
116
116
145
7
Eu
159
159
159
159
8
Eu
159
165
165
159
9
Eg
165
165
165
165
1.000e+40
9.9
1.312e+40
13.0
2.312e+40
22.9
10
Eg
165
169
169
165
1.000e+40
9.9
1.505e+40
14.9
2.505e+40
24.8
11
A1u
169
186
186
169
12
A2g
193
193
193
193
13
Eg
272
272
272
272
4.000e+40
39.6
6.106e+40
60.4
1.011e+41
100.0
14
Eg
272
272
272
272
4.000e+40
39.6
3.174e+40
31.4
7.175e+40
71.0
15
Eu
292
292
292
292
16
Eu
292
328
328
292
17
A2u
328
338
338
371
18
A2g
384
384
384
384
19
Eg
706
706
706
706
3.678e+38
0.4
5.048e+38
0.5
8.726e+38
0.9
20
Eg
706
706
706
706
3.678e+38
0.4
5.198e+38
0.5
8.875e+38
0.9
21
Eu
714
714
714
714
22
Eu
714
715
715
714
23
A2u
830
830
830
836
24
A2g
836
836
836
840
25
A1u
1094
1094
1094
1094
26
A1g
1096
1096
1096
1096
9.524e+40
94.2
2.102e+39
2.1
9.734e+40
96.3
27
Eu
1397
1397
1397
1397
28
Eu
1397
1400
1400
1397
29
Eg
1400
1400
1400
1400
3.361e+40
33.3
5.555e+40
55.0
8.916e+40
88.2
30
Eg
1400
1541
1541
1400
3.361e+40
33.3
3.080e+40
30.5
6.441e+40
63.7
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.