-    TOPAZ     -    Al2SiO4F2

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  Pbnm 
Lattice parameters (Å):  4.6499  8.7968  8.3909 
Angles (°):  90.0  90.0  90.0 

Symmetry (theoretical): 

Space group:  62  Pbnm 
Lattice parameters (Å):  4.5849  8.6722  8.2651 
Angles (°):  90.0  90.0  90.0 

Cell contents: 

Number of atoms:  36 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Al:  0.9039  0.1309  0.0826 
Si:  0.3983  0.9404  0.2500 
O:  0.7939  0.5320  0.2500 
O:  0.4572  0.7551  0.2500 
O:  0.7892  0.0105  0.9087 
F:  0.9022  0.7522  0.0571 
Al:  0.4039  0.3691  0.9174 
Si:  0.8983  0.5596  0.7500 
O:  0.2939  0.9680  0.7500 
O:  0.9572  0.7449  0.7500 
O:  0.2892  0.4895  0.0913 
F:  0.4022  0.7478  0.9429 
Al:  0.0961  0.8691  0.5826 
Si:  0.6017  0.0596  0.7500 
O:  0.2061  0.4680  0.7500 
O:  0.5428  0.2449  0.7500 
O:  0.2108  0.9895  0.4087 
F:  0.0978  0.2478  0.5571 
Al:  0.5961  0.6309  0.4174 
Si:  0.1017  0.4404  0.2500 
O:  0.7061  0.0320  0.2500 
O:  0.0428  0.2551  0.2500 
O:  0.7108  0.5105  0.5913 
F:  0.5978  0.2522  0.4429 
Al:  0.0961  0.8691  0.9174 
O:  0.2108  0.9895  0.0913 
F:  0.0978  0.2478  0.9429 
Al:  0.5961  0.6309  0.0826 
O:  0.7108  0.5105  0.9087 
F:  0.5978  0.2522  0.0571 
Al:  0.9039  0.1309  0.4174 
O:  0.7892  0.0105  0.5913 
F:  0.9022  0.7522  0.4429 
Al:  0.4039  0.3691  0.5826 
O:  0.2892  0.4895  0.4087 
F:  0.4022  0.7478  0.5571 
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
A1g
150
150
150
150
4.024e+38
2.6
9.083e+36
0.1
4.115e+38
2.7
5
B3g
162
162
162
162
1.016e+38
0.7
1.396e+38
0.9
2.412e+38
1.6
6
Au
169
169
169
169
7
B3u
174
176
174
174
8
B1u
178
178
178
180
9
B2g
186
186
186
186
8.051e+36
0.1
1.107e+37
0.1
1.912e+37
0.1
10
Au
188
188
188
188
11
B2u
211
211
212
211
12
B1g
230
230
230
230
1.914e+38
1.2
2.631e+38
1.7
4.545e+38
3.0
13
A1g
237
237
237
237
6.491e+39
42.2
1.954e+38
1.3
6.687e+39
43.5
14
Au
239
239
239
239
15
B2g
243
243
243
243
9.422e+36
0.1
1.296e+37
0.1
2.238e+37
0.1
16
B3g
247
247
247
247
2.117e+37
0.1
2.912e+37
0.2
5.029e+37
0.3
17
B1g
263
263
263
263
8.723e+37
0.6
1.199e+38
0.8
2.072e+38
1.3
18
B2u
264
264
265
264
19
A1g
265
265
269
265
8.744e+39
56.9
8.989e+37
0.6
8.834e+39
57.5
20
B1g
275
275
275
275
1.134e+38
0.7
1.560e+38
1.0
2.694e+38
1.8
21
A1g
282
282
282
282
7.577e+39
49.3
1.424e+38
0.9
7.719e+39
50.2
22
B2g
284
284
284
284
1.257e+37
0.1
1.729e+37
0.1
2.986e+37
0.2
23
B3g
287
287
287
287
1.453e+38
0.9
1.998e+38
1.3
3.451e+38
2.2
24
B3u
291
292
291
291
25
B1u
292
292
292
295
26
Au
295
295
295
297
27
Au
304
304
304
304
28
B2u
304
304
306
304
29
B3u
306
306
310
306
30
B3g
311
311
311
311
1.573e+38
1.0
2.162e+38
1.4
3.735e+38
2.4
31
B1u
327
327
327
330
32
B1g
330
330
330
330
33
A1g
330
330
330
334
1.878e+39
12.2
7.205e+37
0.5
1.950e+39
12.7
34
B3u
335
338
335
335
35
B2g
350
350
350
350
5.567e+36
0.0
7.654e+36
0.0
1.322e+37
0.1
36
B1g
353
353
353
353
1.746e+38
1.1
2.400e+38
1.6
4.146e+38
2.7
37
B1u
362
362
362
366
38
B3g
366
366
366
366
1.584e+37
0.1
2.178e+37
0.1
3.762e+37
0.2
39
B2g
372
372
372
372
8.888e+37
0.6
1.222e+38
0.8
2.111e+38
1.4
40
B3u
373
376
373
373
41
B1g
377
377
377
377
2.631e+37
0.2
3.618e+37
0.2
6.249e+37
0.4
42
B2u
382
382
395
382
43
A1g
398
398
398
398
1.775e+39
11.6
6.732e+37
0.4
1.843e+39
12.0
44
B2u
415
415
417
415
45
B3g
421
421
421
421
2.363e+37
0.2
3.249e+37
0.2
5.611e+37
0.4
46
Au
431
431
431
431
47
B3u
432
439
432
432
48
B2g
439
448
439
439
4.266e+37
0.3
5.866e+37
0.4
1.013e+38
0.7
49
B2u
448
449
449
448
50
A1g
449
451
451
449
1.571e+39
10.2
3.239e+38
2.1
1.895e+39
12.3
51
B1u
451
465
462
458
52
B1g
468
468
468
468
2.039e+36
0.0
2.803e+36
0.0
4.842e+36
0.0
53
B2u
469
469
472
469
54
B1u
472
472
472
472
55
B2g
472
472
478
478
2.900e+37
0.2
3.987e+37
0.3
6.887e+37
0.4
56
B2g
478
478
479
479
1.017e+38
0.7
1.399e+38
0.9
2.416e+38
1.6
57
B3u
479
483
483
483
58
Au
483
484
487
487
59
A1g
487
487
488
488
1.183e+38
0.8
6.121e+37
0.4
1.795e+38
1.2
60
Au
488
488
493
493
61
B3g
493
493
493
493
6.916e+37
0.5
9.510e+37
0.6
1.643e+38
1.1
62
B1g
493
493
496
500
1.094e+38
0.7
1.504e+38
1.0
2.598e+38
1.7
63
B3u
500
510
500
510
64
B3g
510
514
510
510
6.539e+37
0.4
8.991e+37
0.6
1.553e+38
1.0
65
A1g
514
525
514
514
6.413e+38
4.2
4.149e+38
2.7
1.056e+39
6.9
66
B1u
525
531
525
531
67
B3g
531
540
531
531
3.094e+37
0.2
4.254e+37
0.3
7.348e+37
0.5
68
B1g
540
546
540
540
1.443e+38
0.9
1.985e+38
1.3
3.428e+38
2.2
69
B2u
546
547
550
546
70
B1u
555
555
555
557
71
A1g
557
557
557
559
1.132e+39
7.4
5.262e+37
0.3
1.185e+39
7.7
72
Au
559
559
559
568
73
B1g
576
576
576
576
3.095e+37
0.2
4.255e+37
0.3
7.350e+37
0.5
74
B3u
577
582
577
577
75
B2u
585
585
588
585
76
B2g
589
589
589
589
3.916e+36
0.0
5.384e+36
0.0
9.300e+36
0.1
77
B3g
596
596
596
596
2.624e+37
0.2
3.608e+37
0.2
6.232e+37
0.4
78
B2u
602
602
606
602
79
B1u
606
606
607
607
80
A1g
607
607
610
610
5.632e+37
0.4
3.280e+37
0.2
8.912e+37
0.6
81
B3u
610
613
613
613
82
Au
613
628
628
628
83
B1g
628
633
633
633
2.490e+37
0.2
3.423e+37
0.2
5.913e+37
0.4
84
B2g
633
640
640
640
5.969e+37
0.4
8.207e+37
0.5
1.418e+38
0.9
85
A1g
640
665
669
668
2.471e+38
1.6
5.966e+37
0.4
3.068e+38
2.0
86
B1u
669
669
680
680
87
B2g
680
680
680
683
3.637e+37
0.2
5.001e+37
0.3
8.638e+37
0.6
88
B1g
683
683
683
683
7.731e+36
0.1
1.063e+37
0.1
1.836e+37
0.1
89
Au
684
684
684
684
90
B2u
697
697
700
697
91
B3u
706
707
706
706
92
B3g
707
709
707
707
6.226e+37
0.4
8.561e+37
0.6
1.479e+38
1.0
93
Ag
857
857
857
857
1.095e+38
0.7
2.867e+37
0.2
1.382e+38
0.9
94
Ag
857
857
863
857
2.469e+39
16.1
6.464e+38
4.2
3.115e+39
20.3
95
B1u
863
863
863
863
96
Au
863
863
873
873
97
B3u
873
885
890
890
98
B3u
890
902
902
902
99
B1g
902
911
906
911
1.867e+38
1.2
2.567e+38
1.7
4.434e+38
2.9
100
B2u
911
919
919
919
101
A1g
919
928
928
928
1.515e+40
98.6
2.124e+38
1.4
1.536e+40
100.0
102
B1g
928
940
936
940
3.530e+38
2.3
4.854e+38
3.2
8.384e+38
5.5
103
A1g
940
940
940
940
2.242e+39
14.6
1.280e+39
8.3
3.523e+39
22.9
104
B2u
940
977
984
984
105
B2g
984
984
1001
1001
1.311e+39
8.5
1.802e+39
11.7
3.113e+39
20.3
106
B3u
1001
1008
1008
1008
107
B3g
1008
1009
1009
1009
2.834e+38
1.8
3.896e+38
2.5
6.730e+38
4.4
108
B1g
1009
1049
1020
1012
4.421e+38
2.9
6.078e+38
4.0
1.050e+39
6.8
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.