-    DURANGITE     -    NaAlFAsO4

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:  15  C2/c 
Lattice parameters (Å):  6.5300  8.4600  7.0000 
Angles (°):  90.0  115.2  90.0 

Symmetry (theoretical): 

Space group:  15  C2/c 
Lattice parameters (Å):  5.3012  5.3012  6.8930 
Angles (°):  74.8  105.2  75.2 

Cell contents: 

Number of atoms:  16 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Na:  0.6714  0.6714  0.2500 
Al:  0.0000  0.0000  0.0000 
As:  0.3133  0.3133  0.2500 
O:  0.6377  0.2361  0.4209 
O:  0.3083  0.0942  0.1102 
F:  0.9331  0.9331  0.2500 
Al:  0.0000  0.0000  0.5000 
O:  0.2361  0.6377  0.0791 
O:  0.0942  0.3083  0.3898 
Na:  0.3286  0.3286  0.7500 
As:  0.6867  0.6867  0.7500 
O:  0.3623  0.7639  0.5791 
O:  0.6917  0.9058  0.8898 
F:  0.0669  0.0669  0.7500 
O:  0.7639  0.3623  0.9209 
O:  0.9058  0.6917  0.6102 
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
Bg
91
91
91
91
6.264e+38
0.3
8.274e+38
0.4
1.454e+39
0.6
5
Bg
115
115
115
115
3.158e+38
0.1
3.371e+38
0.1
6.529e+38
0.3
6
Bu
119
127
119
135
7
Ag
135
135
135
135
4.910e+39
2.1
3.762e+39
1.6
8.671e+39
3.8
8
Bg
155
155
155
155
1.443e+39
0.6
2.350e+39
1.0
3.793e+39
1.6
9
Au
177
177
177
177
10
Bu
179
179
179
181
11
Bg
209
209
209
209
1.141e+39
0.5
1.782e+39
0.8
2.923e+39
1.3
12
Bu
212
218
212
212
13
Ag
239
239
239
239
4.218e+39
1.8
9.040e+38
0.4
5.122e+39
2.2
14
Au
243
243
244
243
15
Bu
248
248
248
248
16
Bg
248
250
248
248
9.450e+38
0.4
1.105e+39
0.5
2.050e+39
0.9
17
Ag
260
260
260
260
1.093e+40
4.7
4.608e+39
2.0
1.553e+40
6.7
18
Bg
280
280
280
280
8.038e+38
0.3
8.680e+38
0.4
1.672e+39
0.7
19
Bu
287
289
287
288
20
Bu
299
301
299
301
21
Au
301
308
308
308
22
Bg
308
308
310
312
4.064e+39
1.8
4.486e+39
1.9
8.550e+39
3.7
23
Au
312
312
318
312
24
Ag
318
318
343
318
3.005e+40
13.0
6.624e+39
2.9
3.668e+40
15.9
25
Bu
344
351
344
359
26
Au
369
369
371
369
27
Ag
371
371
376
371
5.433e+39
2.4
3.551e+39
1.5
8.983e+39
3.9
28
Bu
383
405
383
421
29
Ag
421
421
421
431
5.377e+39
2.3
3.588e+39
1.6
8.964e+39
3.9
30
Au
431
431
451
449
31
Bg
451
451
462
451
1.130e+40
4.9
1.593e+40
6.9
2.723e+40
11.8
32
Bg
462
462
462
462
1.331e+39
0.6
2.048e+39
0.9
3.379e+39
1.5
33
Bu
472
484
472
474
34
Ag
484
496
484
484
8.061e+40
34.9
6.390e+39
2.8
8.700e+40
37.7
35
Au
496
505
500
496
36
Au
523
523
534
523
37
Bg
534
534
549
534
3.638e+39
1.6
3.918e+39
1.7
7.557e+39
3.3
38
Bu
549
559
558
551
39
Bu
559
564
559
564
40
Au
564
599
590
622
41
Bg
818
818
818
818
1.258e+40
5.5
1.932e+40
8.4
3.190e+40
13.8
42
Ag
819
819
819
819
5.824e+40
25.2
1.542e+40
6.7
7.366e+40
31.9
43
Au
828
828
830
828
44
Bu
830
864
877
831
45
Bu
877
896
886
896
46
Ag
896
908
896
908
2.273e+41
98.5
3.503e+39
1.5
2.308e+41
100.0
47
Au
908
919
919
919
48
Bg
919
939
949
945
2.206e+40
9.6
2.975e+40
12.9
5.181e+40
22.5
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.