-    CALCITE     -    CaCO3

Theoretical atomic positions and lattice parameters at experimental volum from AMCSD; Isotope composition: O-18 

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):  2.5930  2.5930  8.9431 
Angles (°):  90.0  90.0  120.0 

Symmetry (theoretical): 

Space group:  167  R-3c 
Lattice parameters (Å):  6.3310  6.3310  6.3310 
Angles (°):  46.7  46.7  46.7 

Cell contents: 

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

Atomic positions (theoretical):

Ca:  0.0000  0.0000  0.0000 
C:  0.2500  0.2500  0.2500 
O:  0.5050  0.9950  0.2500 
O:  0.9950  0.2500  0.5050 
Ca:  0.5000  0.5000  0.5000 
C:  0.7500  0.7500  0.7500 
O:  0.7500  0.4950  0.0050 
O:  0.2500  0.5050  0.9950 
O:  0.4950  0.0050  0.7500 
O:  0.0050  0.7500  0.4950 
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
89
89
89
103
5
Eu
103
103
103
103
6
Eu
103
123
123
134
7
Eg
151
151
151
151
4.890e+39
7.8
6.410e+39
10.3
1.130e+40
18.1
8
Eg
151
151
151
151
4.890e+39
7.8
7.652e+39
12.2
1.254e+40
20.1
9
A2g
153
153
153
153
10
Eu
243
243
243
243
11
Eu
243
256
256
243
12
Eg
281
281
281
281
1.172e+40
18.7
1.640e+40
26.2
2.812e+40
45.0
13
Eg
281
281
281
281
1.172e+40
18.7
1.288e+40
20.6
2.460e+40
39.3
14
A1u
299
299
299
299
15
A2g
313
313
313
313
16
Eu
323
323
323
323
17
Eu
323
339
339
323
18
A2u
339
395
395
417
19
Eg
667
667
667
667
1.961e+39
3.1
2.228e+39
3.6
4.188e+39
6.7
20
Eg
667
667
667
667
1.961e+39
3.1
1.712e+39
2.7
3.672e+39
5.9
21
Eu
671
671
671
671
22
Eu
671
672
672
671
23
A2u
839
839
839
843
24
A2g
843
843
843
853
25
A1g
1029
1029
1029
1029
7.259e+38
1.2
2.299e+37
0.0
7.489e+38
1.2
26
A1u
1030
1030
1030
1030
6.061e+40
96.9
1.920e+39
3.1
6.253e+40
100.0
27
Eu
1392
1392
1392
1392
28
Eu
1392
1419
1419
1392
29
Eg
1419
1419
1419
1419
2.061e+39
3.3
2.274e+39
3.6
4.335e+39
6.9
30
Eg
1419
1528
1528
1419
2.061e+39
3.3
1.839e+39
2.9
3.901e+39
6.2
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.