-    WITHERITE     -    BaCO3

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. Computed using Troullier-Martisn (fhi) pseudopotentials 

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:  62  Pmcn 
Lattice parameters (Å):  2.8124  4.7119  3.4048 
Angles (°):  90.0  90.0  90.0 

Symmetry (theoretical): 

Space group:  62  Pmcn 
Lattice parameters (Å):  5.3330  9.0005  6.3523 
Angles (°):  90.0  90.0  90.0 

Cell contents: 

Number of atoms:  20 
Number of atom types:  3 
Chemical composition:  0 

Atomic positions (theoretical):

Ba:  0.2500  0.4176  0.7545 
C:  0.2500  0.7561  0.9137 
O:  0.2500  0.8983  0.9052 
O:  0.4579  0.6849  0.9140 
Ba:  0.7500  0.9176  0.7455 
C:  0.7500  0.2561  0.5863 
O:  0.7500  0.3983  0.5948 
O:  0.5421  0.1849  0.5860 
Ba:  0.7500  0.5824  0.2455 
C:  0.7500  0.2439  0.0863 
O:  0.7500  0.1017  0.0948 
O:  0.9579  0.3151  0.0860 
Ba:  0.2500  0.0824  0.2545 
C:  0.2500  0.7439  0.4137 
O:  0.2500  0.6017  0.4052 
O:  0.0421  0.8151  0.4140 
O:  0.5421  0.3151  0.0860 
O:  0.4579  0.8151  0.4140 
O:  0.0421  0.6849  0.9140 
O:  0.9579  0.1849  0.5860 
Atom type  X  Y  Z 

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.

Choose the polarization of the lasers.

I ∥ 
I ⊥ 
I Total 
Horizontal:
Xmin:
Xmax:
Vertical:
Ymin:
Ymax:
 

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
Ag
73
73
73
73
5.087e+38
0.8
3.159e+38
0.5
8.246e+38
1.3
5
B2u
77
77
78
77
6
Au
79
79
79
79
7
B2g
79
79
79
79
1.519e+39
2.4
2.088e+39
3.3
3.607e+39
5.7
8
B1g
90
90
90
90
8.641e+38
1.4
1.188e+39
1.9
2.052e+39
3.3
9
B3g
100
100
100
100
1.871e+38
0.3
2.572e+38
0.4
4.443e+38
0.7
10
Ag
105
105
105
105
8.585e+37
0.1
4.327e+37
0.1
1.291e+38
0.2
11
B3g
144
144
144
144
9.546e+36
0.0
1.313e+37
0.0
2.267e+37
0.0
12
B1u
152
152
152
152
13
B3u
160
162
160
160
14
B2g
162
169
162
162
2.647e+40
42.1
3.639e+40
57.9
6.286e+40
100.0
15
Ag
174
174
174
174
5.170e+38
0.8
3.847e+38
0.6
9.018e+38
1.4
16
B3g
180
180
180
180
1.943e+40
30.9
2.671e+40
42.5
4.614e+40
73.4
17
B2u
182
182
183
182
18
Au
183
183
189
183
19
B1u
189
189
190
190
20
B1g
190
190
194
192
1.179e+39
1.9
1.621e+39
2.6
2.800e+39
4.5
21
B1u
194
194
195
195
22
Ag
195
195
198
220
3.382e+39
5.4
2.339e+39
3.7
5.721e+39
9.1
23
B2g
220
220
220
223
3.905e+39
6.2
5.369e+39
8.5
9.274e+39
14.8
24
B1g
223
223
223
224
8.585e+37
0.1
1.180e+38
0.2
2.039e+38
0.3
25
B3u
224
226
224
230
26
B3g
230
230
230
230
1.082e+38
0.2
1.487e+38
0.2
2.569e+38
0.4
27
B3u
230
237
230
237
28
Au
237
239
237
239
29
B2u
239
241
239
241
30
B2u
241
242
242
242
31
Au
242
252
252
252
32
B1g
252
254
254
254
2.436e+39
3.9
3.349e+39
5.3
5.785e+39
9.2
33
B2g
254
254
254
254
5.138e+36
0.0
7.064e+36
0.0
1.220e+37
0.0
34
B3g
254
262
262
261
4.838e+39
7.7
6.653e+39
10.6
1.149e+40
18.3
35
B1u
262
271
271
267
36
Ag
271
290
294
271
2.077e+39
3.3
1.557e+39
2.5
3.634e+39
5.8
37
Au
695
695
695
695
38
B1g
695
695
695
695
1.046e+39
1.7
1.439e+39
2.3
2.485e+39
4.0
39
B3u
697
697
697
697
40
Ag
697
698
697
697
2.932e+39
4.7
1.979e+39
3.1
4.912e+39
7.8
41
B2g
698
698
698
698
1.635e+38
0.3
2.248e+38
0.4
3.882e+38
0.6
42
B2u
701
701
702
701
43
B3g
702
702
702
702
1.038e+38
0.2
1.427e+38
0.2
2.465e+38
0.4
44
B1u
705
705
705
705
45
B1u
840
840
840
841
46
Ag
841
841
841
851
5.819e+36
0.0
4.271e+35
0.0
6.246e+36
0.0
47
B3g
867
867
867
867
1.058e+36
0.0
1.455e+36
0.0
2.513e+36
0.0
48
B2u
868
868
868
868
49
B3g
1070
1070
1070
1070
3.304e+36
0.0
4.543e+36
0.0
7.847e+36
0.0
50
B2u
1072
1072
1072
1072
51
Ag
1072
1072
1072
1072
4.821e+40
76.7
6.899e+38
1.1
4.890e+40
77.8
52
B1u
1072
1072
1072
1073
53
Au
1394
1394
1394
1394
54
B1g
1412
1412
1412
1412
4.332e+38
0.7
5.956e+38
0.9
1.029e+39
1.6
55
B1u
1425
1425
1425
1425
56
Ag
1430
1430
1430
1430
4.461e+38
0.7
2.373e+38
0.4
6.835e+38
1.1
57
B2u
1438
1438
1438
1438
58
B3u
1438
1451
1451
1438
59
B2g
1451
1528
1528
1451
2.019e+39
3.2
2.776e+39
4.4
4.795e+39
7.6
60
B3g
1528
1533
1534
1528
1.978e+39
3.1
2.720e+39
4.3
4.698e+39
7.5
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.