-    GRANDREEFITE     -    Pb2SO4F2

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. Computed using Teter "extended norm-conserving" pseudopotentials. 

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):  8.6670  4.4419  14.2420 
Angles (°):  90.0  107.4  90.0 

Symmetry (theoretical): 

Space group:  15  C2/c 
Lattice parameters (Å):  9.4528  7.3731  9.4528 
Angles (°):  121.2  153.3  67.6 

Cell contents: 

Number of atoms:  18 
Number of atom types:  4 
Chemical composition:  0 

Atomic positions (theoretical):

Pb:  0.6686  0.2335  0.5921 
S:  0.0417  0.2500  0.2917 
F:  0.2764  0.3714  0.1558 
O:  0.2465  0.1151  0.3522 
O:  0.9449  0.3928  0.1556 
Pb:  0.3586  0.2665  0.9351 
F:  0.7844  0.1286  0.4050 
O:  0.2370  0.3849  0.6313 
O:  0.7629  0.1072  0.0521 
Pb:  0.3314  0.7665  0.4079 
S:  0.9583  0.7500  0.7083 
F:  0.7236  0.6286  0.8442 
O:  0.7535  0.8849  0.6478 
O:  0.0551  0.6072  0.8444 
Pb:  0.6414  0.7335  0.0649 
F:  0.2156  0.8714  0.5950 
O:  0.7630  0.6151  0.3687 
O:  0.2371  0.8928  0.9479 
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
Bu
45
46
45
45
5
Au
46
48
48
46
6
Ag
48
50
48
48
2.488e+39
1.2
4.281e+38
0.2
2.916e+39
1.4
7
Bg
58
58
58
58
9.032e+38
0.4
1.204e+39
0.6
2.107e+39
1.0
8
Bg
59
59
59
59
5.383e+37
0.0
7.402e+37
0.0
1.279e+38
0.1
9
Ag
61
61
61
61
2.443e+39
1.1
1.392e+39
0.7
3.835e+39
1.8
10
Bu
90
91
90
90
11
Au
91
95
98
91
12
Bg
98
98
98
98
13
Bg
98
101
101
101
9.000e+39
4.2
1.418e+40
6.7
2.318e+40
10.9
14
Bg
101
105
108
102
1.036e+40
4.9
1.488e+40
7.0
2.524e+40
11.8
15
Bu
108
108
108
108
16
Ag
108
110
110
110
6.939e+39
3.3
4.186e+39
2.0
1.112e+40
5.2
17
Bg
110
119
113
119
2.047e+38
0.1
2.356e+38
0.1
4.404e+38
0.2
18
Au
119
125
125
125
19
Ag
125
135
135
134
4.237e+39
2.0
3.270e+39
1.5
7.507e+39
3.5
20
Bg
135
147
135
135
6.777e+39
3.2
9.981e+39
4.7
1.676e+40
7.9
21
Ag
147
157
147
147
2.762e+40
13.0
4.086e+39
1.9
3.171e+40
14.9
22
Au
158
158
164
158
23
Bu
164
165
164
171
24
Au
171
171
179
179
25
Ag
179
179
187
187
1.349e+40
6.3
1.240e+40
5.8
2.589e+40
12.1
26
Bu
187
187
192
194
27
Bu
194
197
194
197
28
Bg
197
211
197
211
1.159e+39
0.5
1.880e+39
0.9
3.039e+39
1.4
29
Au
211
214
214
214
30
Bg
214
222
222
222
8.941e+38
0.4
1.145e+39
0.5
2.039e+39
1.0
31
Ag
222
233
233
233
1.108e+40
5.2
9.407e+39
4.4
2.048e+40
9.6
32
Bg
233
243
236
239
7.301e+39
3.4
9.719e+39
4.6
1.702e+40
8.0
33
Au
243
248
248
243
34
Ag
248
270
270
248
5.792e+39
2.7
4.155e+39
1.9
9.948e+39
4.7
35
Bg
270
270
278
270
3.271e+39
1.5
3.762e+39
1.8
7.033e+39
3.3
36
Bu
278
283
292
312
37
Au
422
422
422
422
38
Ag
439
439
439
439
1.335e+40
6.3
2.209e+39
1.0
1.556e+40
7.3
39
Ag
454
454
454
454
1.626e+40
7.6
2.172e+40
10.2
3.798e+40
17.8
40
Au
475
475
475
475
41
Au
565
565
566
565
42
Ag
566
566
573
566
5.126e+39
2.4
3.839e+39
1.8
8.964e+39
4.2
43
Bu
587
597
587
587
44
Bg
602
602
602
602
1.796e+39
0.8
1.945e+39
0.9
3.741e+39
1.8
45
Bg
604
604
604
604
3.742e+39
1.8
5.470e+39
2.6
9.213e+39
4.3
46
Bu
610
610
610
620
47
Au
962
962
963
962
48
Ag
963
963
963
963
2.126e+41
99.8
5.042e+38
0.2
2.131e+41
100.0
49
Bu
1010
1048
1010
1010
50
Au
1048
1048
1048
1048
51
Ag
1048
1078
1078
1048
3.064e+40
14.4
4.342e+39
2.0
3.499e+40
16.4
52
Bg
1078
1084
1102
1078
7.584e+40
35.6
1.128e+41
52.9
1.886e+41
88.5
53
Bg
1102
1102
1120
1102
6.848e+40
32.1
8.909e+40
41.8
1.576e+41
73.9
54
Bu
1120
1120
1131
1170
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.