-    LACROIXITE     -    NaAl(PO4)F

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):  6.4140  8.2070  6.8850 
Angles (°):  90.0  115.5  90.0 

Symmetry (theoretical): 

Space group:  15  C2/c 
Lattice parameters (Å):  5.1348  5.1348  6.7564 
Angles (°):  74.7  105.3  75.8 

Cell contents: 

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

Atomic positions (theoretical):

Na:  0.6686  0.6686  0.2500 
Al:  0.0000  0.0000  1.0000 
F:  0.9293  0.9293  0.2500 
P:  0.3177  0.3177  0.2500 
O:  0.3063  0.1123  0.1210 
O:  0.6240  0.2390  0.4050 
Al:  0.0000  0.0000  0.5000 
O:  0.1123  0.3063  0.3790 
O:  0.2390  0.6240  0.0950 
Na:  0.3314  0.3314  0.7500 
F:  0.0707  0.0707  0.7500 
P:  0.6823  0.6823  0.7500 
O:  0.6937  0.8877  0.8790 
O:  0.3760  0.7610  0.5950 
O:  0.8877  0.6937  0.6210 
O:  0.7610  0.3760  0.9050 
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
95
95
95
95
1.330e+38
0.3
1.721e+38
0.4
3.051e+38
0.7
5
Bu
102
111
102
123
6
Bg
131
131
131
131
4.309e+38
1.0
7.022e+38
1.6
1.133e+39
2.5
7
Ag
169
169
169
169
2.126e+39
4.7
9.731e+38
2.2
3.099e+39
6.9
8
Bg
192
192
192
192
3.585e+38
0.8
5.326e+38
1.2
8.910e+38
2.0
9
Bu
197
199
197
198
10
Au
200
200
200
200
11
Bg
217
217
217
217
8.251e+37
0.2
1.135e+38
0.3
1.960e+38
0.4
12
Bu
234
244
234
235
13
Bu
288
290
288
288
14
Bg
294
294
294
294
4.949e+38
1.1
6.069e+38
1.3
1.102e+39
2.5
15
Ag
299
299
299
299
9.056e+38
2.0
2.369e+38
0.5
1.143e+39
2.5
16
Au
300
300
300
300
17
Bu
318
320
318
320
18
Ag
320
320
320
326
1.684e+40
37.5
4.245e+38
0.9
1.727e+40
38.4
19
Bg
326
326
326
327
3.555e+38
0.8
4.888e+38
1.1
8.443e+38
1.9
20
Bg
346
346
346
346
1.801e+37
0.0
2.988e+37
0.1
4.789e+37
0.1
21
Bu
361
364
361
366
22
Au
366
366
366
367
23
Ag
377
377
377
377
3.934e+39
8.7
1.054e+39
2.3
4.987e+39
11.1
24
Bu
387
387
387
389
25
Au
389
389
412
400
26
Au
418
418
426
418
27
Bu
426
434
433
434
28
Ag
434
465
434
465
2.281e+39
5.1
1.553e+39
3.5
3.834e+39
8.5
29
Au
465
498
498
482
30
Ag
498
510
523
498
5.677e+39
12.6
7.389e+38
1.6
6.416e+39
14.3
31
Bg
524
524
524
524
5.673e+38
1.3
9.102e+38
2.0
1.477e+39
3.3
32
Au
546
546
570
546
33
Bu
570
578
579
579
34
Au
587
587
598
587
35
Bg
598
598
609
598
2.201e+39
4.9
2.547e+39
5.7
4.748e+39
10.6
36
Ag
609
609
611
609
1.404e+40
31.2
2.418e+39
5.4
1.646e+40
36.6
37
Bu
614
622
614
622
38
Bg
622
631
622
636
9.628e+38
2.1
1.519e+39
3.4
2.482e+39
5.5
39
Au
636
636
641
636
40
Bu
641
659
641
678
41
Au
986
986
987
986
42
Ag
987
987
1000
987
4.406e+40
98.0
9.090e+38
2.0
4.497e+40
100.0
43
Bg
1008
1008
1008
1008
3.166e+39
7.0
4.877e+39
10.8
8.043e+39
17.9
44
Bu
1024
1036
1024
1030
45
Ag
1036
1040
1036
1036
2.078e+40
46.2
2.730e+39
6.1
2.351e+40
52.3
46
Bu
1055
1067
1055
1067
47
Au
1067
1115
1115
1115
48
Bg
1115
1154
1170
1152
3.684e+39
8.2
4.538e+39
10.1
8.222e+39
18.3
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.