-    BUTSCHLIITE     -    K2Ca(CO3)2

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:  166  R-3m 
Lattice parameters (Å):  5.3870  5.3870  18.1600 
Angles (°):  90  90  120 

Symmetry (theoretical): 

Space group:  166  R-3m 
Lattice parameters (Å):  6.5844  6.5844  6.5844 
Angles (°):  46.23  46.23  46.23 

Cell contents: 

Number of atoms:  11 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

K:  0.2012  0.2012  0.2012 
Ca:  0.0000  0.0000  0.0000 
C:  0.5803  0.5803  0.5803 
O:  0.7221  0.2945  0.7221 
O:  0.2945  0.7221  0.7221 
O:  0.7221  0.7221  0.2945 
K:  0.7988  0.7988  0.7988 
C:  0.4197  0.4197  0.4197 
O:  0.2779  0.7055  0.2779 
O:  0.7055  0.2779  0.2779 
O:  0.2779  0.2779  0.7055 
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
A2g
87
87
87
87
5
Eg
106
106
106
106
1.003e+40
20.4
1.675e+40
34.1
2.678e+40
54.4
6
Eg
106
106
106
106
1.003e+40
20.4
1.171e+40
23.8
2.174e+40
44.2
7
A1u
122
122
122
122
8
A1g
143
143
143
143
4.961e+38
1.0
1.045e+37
0.0
5.065e+38
1.0
9
Eu
159
159
159
159
10
Eu
159
160
160
159
11
Eg
161
161
161
161
9.794e+38
2.0
1.157e+39
2.4
2.136e+39
4.3
12
Eg
161
161
161
161
9.794e+38
2.0
1.636e+39
3.3
2.615e+39
5.3
13
A2u
184
184
184
196
14
Eu
196
196
196
196
15
Eu
196
223
223
216
16
Eg
265
265
265
265
1.262e+40
25.7
1.637e+40
33.3
2.899e+40
59.0
17
Eg
265
265
265
265
1.262e+40
25.7
1.965e+40
40.0
3.227e+40
65.6
18
A1g
289
289
289
289
7.934e+39
16.1
9.926e+38
2.0
8.926e+39
18.2
19
Eu
341
341
341
341
20
Eu
341
361
361
341
21
A2u
361
402
402
414
22
Eg
690
690
690
690
1.285e+39
2.6
1.523e+39
3.1
2.809e+39
5.7
23
Eg
690
690
690
690
1.285e+39
2.6
1.563e+39
3.2
2.849e+39
5.8
24
Eu
695
695
695
695
25
Eu
695
695
695
695
26
A2u
844
844
844
861
27
A1g
876
876
876
876
3.487e+38
0.7
2.601e+38
0.5
6.087e+38
1.2
28
A2u
1120
1120
1120
1122
29
A1g
1122
1122
1122
1122
4.772e+40
97.0
1.452e+39
3.0
4.917e+40
100.0
30
Eg
1434
1434
1434
1434
5.872e+39
11.9
8.308e+39
16.9
1.418e+40
28.8
31
Eg
1434
1434
1434
1434
5.872e+39
11.9
7.804e+39
15.9
1.368e+40
27.8
32
Eu
1463
1463
1463
1463
33
Eu
1463
1589
1589
1463
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.