-    ARAGONITE     -    CaCO3

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:  62  Pnma 
Lattice parameters (Å):  4.9608  7.9688  5.7411 
Angles (°):  90  90  90 

Symmetry (theoretical): 

Space group:  62  Pnma 
Lattice parameters (Å):  6.7250  5.8671  5.7657 
Angles (°):  90  90  90 

Cell contents: 

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

Atomic positions (theoretical):

Ca:  0.2500  0.3130  0.0213 
C:  0.2500  0.7831  0.0141 
O:  0.2500  0.9428  0.8674 
O:  0.4106  0.6974  0.0979 
Ca:  0.7500  0.1870  0.5213 
C:  0.7500  0.7169  0.5141 
O:  0.7500  0.5572  0.3674 
O:  0.5894  0.8026  0.5979 
Ca:  0.7500  0.6870  0.9787 
C:  0.7500  0.2169  0.9859 
O:  0.7500  0.0572  0.1326 
O:  0.9106  0.3026  0.9021 
Ca:  0.2500  0.8130  0.4787 
C:  0.2500  0.2831  0.4859 
O:  0.2500  0.4428  0.6326 
O:  0.0894  0.1974  0.4021 
O:  0.5894  0.3026  0.9021 
O:  0.4106  0.1974  0.4021 
O:  0.0894  0.6974  0.0979 
O:  0.9106  0.8026  0.5979 
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
Au
91
91
91
91
5
B2g
98
98
98
98
3.700e+37
0.0
5.087e+37
0.0
8.787e+37
0.1
6
A1g
102
102
102
102
7.669e+38
0.6
1.878e+38
0.2
9.546e+38
0.8
7
B1u
117
117
117
117
8
B3g
119
119
119
119
3.160e+38
0.3
4.345e+38
0.4
7.504e+38
0.6
9
Au
121
121
121
121
10
B2g
122
122
122
122
2.404e+38
0.2
3.306e+38
0.3
5.710e+38
0.5
11
B1g
129
129
129
129
9.010e+38
0.8
1.239e+39
1.0
2.140e+39
1.8
12
A1g
134
134
134
134
7.362e+38
0.6
1.529e+38
0.1
8.890e+38
0.7
13
B3u
136
159
136
136
14
B3u
162
165
162
162
15
B1g
168
168
168
168
3.753e+39
3.2
5.161e+39
4.3
8.914e+39
7.5
16
B3g
178
178
178
178
7.124e+38
0.6
9.796e+38
0.8
1.692e+39
1.4
17
B1g
180
180
180
180
5.375e+39
4.5
7.390e+39
6.2
1.276e+40
10.8
18
Au
183
183
183
183
19
B2u
189
189
193
189
20
B2u
211
211
221
211
21
B2g
221
221
226
221
3.985e+39
3.4
5.480e+39
4.6
9.465e+39
8.0
22
A1g
226
226
233
226
1.612e+40
13.6
1.209e+40
10.2
2.821e+40
23.8
23
B1u
251
251
251
257
24
B3g
269
269
269
269
1.212e+37
0.0
1.667e+37
0.0
2.879e+37
0.0
25
B1u
270
270
270
272
26
B2u
272
272
274
274
27
B3g
274
274
278
278
4.535e+37
0.0
6.235e+37
0.1
1.077e+38
0.1
28
A1g
278
278
295
295
1.251e+39
1.1
9.255e+38
0.8
2.177e+39
1.8
29
Au
295
295
302
302
30
B1g
302
302
302
302
5.943e+38
0.5
8.172e+38
0.7
1.412e+39
1.2
31
B2g
302
302
306
306
1.535e+39
1.3
2.110e+39
1.8
3.645e+39
3.1
32
B3u
306
362
310
328
33
B2u
362
364
364
362
34
A1g
364
366
386
364
1.291e+40
10.9
9.663e+39
8.1
2.257e+40
19.0
35
B1u
386
386
386
386
1.967e+36
0.0
2.705e+36
0.0
4.671e+36
0.0
36
B3g
386
386
417
433
5.431e+37
0.0
7.468e+37
0.1
1.290e+38
0.1
37
Au
636
636
636
636
38
B1g
643
643
643
643
1.233e+39
1.0
1.695e+39
1.4
2.928e+39
2.5
39
B3u
644
645
644
644
40
B2g
656
656
656
656
1.753e+39
1.5
2.410e+39
2.0
4.163e+39
3.5
41
A1g
741
741
741
741
1.735e+39
1.5
1.239e+39
1.0
2.974e+39
2.5
42
B1u
742
742
742
744
43
B3g
745
745
745
745
4.544e+37
0.0
6.248e+37
0.1
1.079e+38
0.1
44
B2u
746
746
748
746
45
B1u
882
882
882
882
1.511e+37
0.0
3.467e+36
0.0
1.857e+37
0.0
46
B1g
883
883
883
883
1.544e+38
0.1
3.545e+37
0.0
1.899e+38
0.2
47
B2u
883
883
883
883
48
B3g
883
883
889
890
1.174e+37
0.0
1.614e+37
0.0
2.787e+37
0.0
49
B1u
1093
1093
1093
1093
50
B2u
1094
1094
1094
1094
51
B3g
1096
1096
1096
1096
2.074e+39
1.7
2.852e+39
2.4
4.926e+39
4.2
52
A1g
1096
1096
1096
1096
1.165e+41
98.2
2.164e+39
1.8
1.187e+41
100.0
53
B3u
1365
1379
1365
1365
54
B2g
1379
1382
1379
1379
3.088e+38
0.3
4.246e+38
0.4
7.335e+38
0.6
55
Au
1382
1463
1382
1382
56
B1g
1463
1493
1463
1463
2.237e+39
1.9
3.075e+39
2.6
5.312e+39
4.5
57
A1g
1493
1493
1493
1493
9.143e+39
7.7
6.617e+39
5.6
1.576e+40
13.3
58
B1u
1512
1512
1512
1526
59
B3g
1526
1526
1526
1535
6.988e+38
0.6
9.609e+38
0.8
1.660e+39
1.4
60
B2u
1535
1535
1608
1575
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.