-    JOHACHIDOLITE     -    CaAlB3O7

Theoretical atomic positions and lattice parameters at experimental volum from 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:  67  Cmma 
Lattice parameters (Å):  7.9670  11.7230  4.3718 
Angles (°):  90  90  90 

Symmetry (theoretical): 

Space group:  67  Cmma 
Lattice parameters (Å):  7.3343  7.3343  4.2299 
Angles (°):  90  90  63.80 

Cell contents: 

Number of atoms:  24 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Ca:  0.5000  0.0000  0.0000 
Al:  0.0000  0.0000  0.0000 
Al:  0.2500  0.7500  0.5000 
B:  0.1270  0.1270  0.4074 
B:  0.2500  0.2500  0.4067 
O:  0.1183  0.1183  0.7420 
O:  0.2219  0.9325  0.2430 
Ca:  0.0000  0.5000  0.0000 
Al:  0.5000  0.5000  0.0000 
B:  0.3730  0.3730  0.4074 
O:  0.3817  0.3817  0.7420 
O:  0.2781  0.5675  0.2430 
B:  0.6270  0.6270  0.5926 
B:  0.7500  0.7500  0.5933 
O:  0.6183  0.6183  0.2580 
O:  0.4325  0.7219  0.7570 
B:  0.8730  0.8730  0.5926 
O:  0.8817  0.8817  0.2580 
O:  0.0675  0.7781  0.7570 
Al:  0.7500  0.2500  0.5000 
O:  0.7781  0.0675  0.7570 
O:  0.7219  0.4325  0.7570 
O:  0.5675  0.2781  0.2430 
O:  0.9325  0.2219  0.2430 
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
B2g
-266
-266
-266
-266
2
B3g
-180
-180
-180
-180
3
B2u
-142
-142
-134
-142
4
Ac
0
0
0
0
5
Ac
0
0
0
0
6
Ac
0
0
0
0
7
B3u
28
40
28
28
8
B1u
103
103
103
112
9
B3g
139
139
139
139
10
Au
140
140
140
140
11
B2u
152
152
156
152
12
B3u
156
158
189
156
13
B1g
189
189
206
189
1.400e+52
0.0
1.925e+52
0.0
3.325e+52
0.0
14
B1u
206
206
208
208
15
B2g
208
208
213
216
16
B1u
216
216
216
217
17
B3u
218
220
218
218
18
B2u
221
221
222
221
19
Au
254
254
254
254
20
B2g
282
282
282
282
21
B1g
292
292
292
292
22
Ag
310
310
310
310
1.437e+54
0.5
7.514e+53
0.2
2.188e+54
0.7
23
B3u
312
313
312
312
24
B3g
348
348
348
348
25
Ag
357
357
357
357
2.336e+56
73.5
8.405e+55
26.5
3.176e+56
100.0
26
Au
364
364
364
364
27
B2g
381
381
381
381
28
B1u
385
385
385
385
29
B1g
418
418
418
418
30
B2u
431
431
434
431
31
B3u
434
434
445
434
32
Au
450
450
450
450
33
B3u
483
483
483
483
34
B1u
485
485
485
485
35
B1g
507
507
507
507
36
B1u
517
517
517
521
37
Ag
521
521
521
529
1.970e+53
0.1
9.886e+52
0.0
2.959e+53
0.1
38
B2u
535
535
538
535
39
B1u
555
555
555
566
40
B3g
566
566
566
567
41
Au
582
582
582
582
42
Ag
600
600
600
600
43
B2g
601
601
601
601
44
B3u
615
616
615
615
45
B2u
623
623
624
623
46
B1u
686
686
686
693
47
B3g
693
693
693
697
48
Au
741
741
741
741
49
B2u
745
745
757
745
50
B1u
757
757
763
757
51
Ag
780
780
780
780
7.611e+52
0.0
7.597e+52
0.0
1.521e+53
0.0
52
B2u
804
804
809
804
53
B3g
810
810
810
810
54
B3u
833
833
833
833
55
B1g
840
840
840
840
56
B2g
874
874
874
874
57
Ag
909
909
909
909
9.439e+54
3.0
3.064e+54
1.0
1.250e+55
3.9
58
B3u
940
944
940
940
59
B2g
947
947
947
947
60
B3g
968
968
968
968
61
B1g
982
982
982
982
62
B2u
995
995
1001
995
63
B1u
1001
1001
1004
1006
64
Au
1057
1057
1057
1057
65
B3g
1082
1082
1082
1082
66
B2u
1084
1084
1084
1084
67
Ag
1086
1086
1086
1086
3.407e+53
0.1
4.269e+53
0.1
7.677e+53
0.2
68
B1u
1106
1106
1106
1124
69
B1u
1141
1141
1141
1143
70
Ag
1221
1221
1221
1221
1.698e+51
0.0
1.904e+51
0.0
3.603e+51
0.0
71
B3g
1547
1547
1547
1547
72
B2u
1548
1548
1549
1548
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.