-    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 Teter "extended norm-conserving" pseudopotential for Ba. 

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):  5.2523  8.8533  6.1868 
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  0.4163  0.7538 
C:  0.2500  0.7552  0.9154 
O:  0.2500  0.8998  0.9086 
O:  0.4611  0.6829  0.9151 
Ba:  0.7500  0.9163  0.7462 
C:  0.7500  0.2552  0.5846 
O:  0.7500  0.3998  0.5914 
O:  0.5389  0.1829  0.5849 
Ba:  0.7500  0.5837  0.2462 
C:  0.7500  0.2448  0.0846 
O:  0.7500  0.1002  0.0914 
O:  0.9611  0.3171  0.0849 
Ba:  0.2500  0.0837  0.2538 
C:  0.2500  0.7448  0.4154 
O:  0.2500  0.6002  0.4086 
O:  0.0389  0.8171  0.4151 
O:  0.5389  0.3171  0.0849 
O:  0.4611  0.8171  0.4151 
O:  0.0389  0.6829  0.9151 
O:  0.9611  0.1829  0.5849 
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
A1g
72
72
72
72
3.437e+38
0.3
2.461e+38
0.2
5.898e+38
0.5
5
B2u
77
77
77
77
6
B2g
80
80
80
80
1.689e+37
0.0
2.323e+37
0.0
4.012e+37
0.0
7
B2g
80
80
80
80
1.731e+39
1.6
2.380e+39
2.2
4.111e+39
3.7
8
B1g
94
94
94
94
3.423e+39
3.1
4.707e+39
4.3
8.130e+39
7.3
9
B3g
98
98
98
98
7.525e+36
0.0
1.035e+37
0.0
1.787e+37
0.0
10
A1g
105
105
105
105
1.514e+39
1.4
1.086e+39
1.0
2.599e+39
2.3
11
B3g
139
139
139
139
1.532e+38
0.1
2.107e+38
0.2
3.639e+38
0.3
12
B2g
142
142
142
142
4.660e+40
42.1
6.407e+40
57.9
1.107e+41
100.0
13
B1u
145
145
145
146
14
B3u
146
150
146
147
15
A1g
155
155
155
155
3.387e+39
3.1
2.388e+39
2.2
5.775e+39
5.2
16
Au
157
157
157
157
17
B2u
157
157
160
157
18
B3g
160
160
161
160
3.549e+40
32.1
4.880e+40
44.1
8.429e+40
76.2
19
B1u
161
161
165
165
20
B1g
165
165
167
167
6.647e+39
6.0
9.140e+39
8.3
1.579e+40
14.3
21
A1g
167
167
167
177
1.120e+40
10.1
8.331e+39
7.5
1.953e+40
17.6
22
B1u
178
178
178
184
23
B1g
184
184
184
186
1.290e+38
0.1
1.774e+38
0.2
3.064e+38
0.3
24
B3u
186
186
186
190
25
B2g
190
190
190
195
3.785e+39
3.4
5.204e+39
4.7
8.989e+39
8.1
26
B3u
195
201
195
201
27
B3g
201
205
201
205
1.399e+39
1.3
1.923e+39
1.7
3.322e+39
3.0
28
B2u
205
206
206
206
29
Au
206
213
213
213
30
Au
213
218
218
218
31
B2g
218
229
229
229
1.229e+37
0.0
1.689e+37
0.0
2.918e+37
0.0
32
B1g
229
235
235
235
8.327e+39
7.5
1.145e+40
10.3
1.978e+40
17.9
33
Ag
235
235
235
235
2.523e+37
0.0
1.891e+37
0.0
4.414e+37
0.0
34
Ag
235
238
238
238
6.619e+39
6.0
4.964e+39
4.5
1.158e+40
10.5
35
B3g
238
246
246
245
5.608e+39
5.1
7.711e+39
7.0
1.332e+40
12.0
36
B1u
246
278
279
255
37
B1g
682
682
682
682
3.317e+39
3.0
4.561e+39
4.1
7.878e+39
7.1
38
A1g
683
683
683
683
6.316e+39
5.7
4.519e+39
4.1
1.083e+40
9.8
39
Au
684
684
684
684
40
B3u
686
687
686
686
41
B2u
687
688
688
687
42
B2g
688
689
690
688
1.419e+39
1.3
1.951e+39
1.8
3.370e+39
3.0
43
B3g
694
694
694
694
1.232e+39
1.1
1.694e+39
1.5
2.926e+39
2.6
44
B1u
697
697
697
697
45
B1u
837
837
837
838
46
A1g
838
838
838
848
9.191e+37
0.1
5.501e+35
0.0
9.246e+37
0.1
47
B3g
867
867
867
867
48
B2u
868
868
868
868
49
B3g
1070
1070
1070
1070
3.306e+36
0.0
4.546e+36
0.0
7.852e+36
0.0
50
B2u
1071
1071
1071
1071
51
B1u
1072
1072
1072
1072
52
Ag
1072
1072
1072
1072
7.874e+40
71.1
9.787e+38
0.9
7.972e+40
72.0
53
Au
1394
1394
1394
1394
54
B1g
1410
1410
1410
1410
5.136e+37
0.0
7.062e+37
0.1
1.220e+38
0.1
55
B1u
1419
1419
1419
1419
56
A1g
1419
1419
1419
1419
4.500e+38
0.4
1.406e+38
0.1
5.906e+38
0.5
57
B2u
1435
1435
1436
1435
58
B3u
1436
1437
1437
1436
59
B2g
1437
1524
1524
1437
5.543e+39
5.0
7.622e+39
6.9
1.317e+40
11.9
60
B3g
1524
1534
1533
1524
6.924e+39
6.3
9.520e+39
8.6
1.644e+40
14.9
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.