-    NEIGHBORITE     -    NaMgF3

 

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):  5.3603  5.4884  7.6660 
Angles (°):  90  90  90 

Symmetry (theoretical): 

Space group:  62  Pnma 
Lattice parameters (Å):  4.4358  5.0410  6.7626 
Angles (°):  90  90  90 

Cell contents: 

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

Atomic positions (theoretical):

Na:  0.9601  0.0937  0.2500 
Mg:  0.0000  0.5000  0.0000 
F:  0.1158  0.4706  0.2500 
F:  0.6657  0.3140  0.0561 
Na:  0.4601  0.4063  0.7500 
Mg:  0.5000  1.0000  0.0000 
F:  0.6158  0.0294  0.7500 
F:  0.1657  0.1860  0.9439 
Na:  0.0399  0.9063  0.7500 
Mg:  0.0000  0.5000  0.5000 
F:  0.8842  0.5294  0.7500 
F:  0.3343  0.6860  0.5561 
Na:  0.5399  0.5937  0.2500 
Mg:  0.5000  1.0000  0.5000 
F:  0.3842  0.9706  0.2500 
F:  0.8343  0.8140  0.4439 
F:  0.3343  0.6860  0.9439 
F:  0.8343  0.8140  0.0561 
F:  0.6657  0.3140  0.4439 
F:  0.1657  0.1860  0.5561 
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
Au
136
136
136
136
5
B3u
185
185
185
185
6
B1u
203
203
203
212
7
B2u
221
221
225
221
8
B1g
225
225
229
225
1.962e+37
2.7
2.698e+37
3.7
4.659e+37
6.5
9
A1g
229
229
230
229
6.562e+38
90.9
5.473e+37
7.6
7.109e+38
98.4
10
Au
240
240
240
240
11
A1g
250
250
250
250
4.044e+38
56.0
4.151e+37
5.7
4.460e+38
61.8
12
Au
255
255
255
255
13
B3g
266
266
266
266
14
B3u
280
281
280
280
15
B1g
281
284
281
281
1.538e+38
21.3
2.115e+38
29.3
3.654e+38
50.6
16
B2g
289
289
289
289
3.551e+37
4.9
4.882e+37
6.8
8.433e+37
11.7
17
Au
294
294
294
294
18
B1u
295
295
295
295
19
B2u
306
306
313
306
20
A1g
313
313
317
313
1.367e+38
18.9
9.032e+37
12.5
2.270e+38
31.4
21
B3u
319
322
319
319
22
B2u
323
323
323
323
23
B3g
323
323
326
323
2.028e+37
2.8
2.789e+37
3.9
4.817e+37
6.7
24
B1g
326
326
330
326
1.128e+36
0.2
1.551e+36
0.2
2.679e+36
0.4
25
B2g
335
335
335
335
6.674e+36
0.9
9.177e+36
1.3
1.585e+37
2.2
26
A1g
347
347
347
347
6.679e+38
92.5
5.433e+37
7.5
7.222e+38
100.0
27
B1u
360
360
360
363
28
B2u
363
363
367
379
29
B3u
380
417
380
380
30
Au
417
418
417
417
31
B1u
433
433
433
449
32
B3g
449
449
449
458
2.572e+37
3.6
3.537e+37
4.9
6.110e+37
8.5
33
B1g
458
458
458
479
1.368e+37
1.9
1.881e+37
2.6
3.250e+37
4.5
34
B2u
488
488
488
488
35
A1g
493
493
493
493
2.136e+38
29.6
1.093e+38
15.1
3.229e+38
44.7
36
B3u
503
504
503
503
37
B1g
504
505
504
504
7.590e+35
0.1
1.044e+36
0.1
1.803e+36
0.2
38
B3u
520
526
520
520
39
B2g
526
528
526
526
9.595e+36
1.3
1.319e+37
1.8
2.279e+37
3.2
40
B2u
529
529
547
529
41
A1g
547
547
562
547
6.008e+38
83.2
1.014e+37
1.4
6.110e+38
84.6
42
B1g
570
570
570
570
4.040e+36
0.6
5.554e+36
0.8
9.594e+36
1.3
43
B1u
586
586
586
597
44
B3g
597
597
597
599
1.778e+37
2.5
2.444e+37
3.4
4.222e+37
5.8
45
B2g
599
599
599
601
2.060e+38
28.5
2.832e+38
39.2
4.892e+38
67.7
46
B2u
601
601
604
604
47
B3u
604
605
605
605
48
A1g
605
615
615
614
1.029e+38
14.3
7.688e+37
10.6
1.798e+38
24.9
49
Au
615
646
616
615
50
B3u
648
662
648
648
51
B1g
678
678
678
678
5.573e+35
0.1
7.664e+35
0.1
1.324e+36
0.2
52
B3g
681
681
681
681
2.735e+36
0.4
3.760e+36
0.5
6.495e+36
0.9
53
B2u
683
683
687
683
54
B2g
705
705
705
705
4.781e+36
0.7
6.574e+36
0.9
1.136e+37
1.6
55
Au
764
764
764
764
56
B3u
771
785
771
771
57
B1u
785
788
785
786
58
B2u
788
814
814
788
59
Au
814
819
819
814
60
B1u
819
824
864
883
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.