-    HAFNON     -    HfSiO4

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:  141  I4_1/amd 
Lattice parameters (Å):       
Angles (°):       

Symmetry (theoretical): 

Space group:  141  I4_1/amd 
Lattice parameters (Å):  5.4471  5.4471  5.4471 
Angles (°):  106.8  106.8  114.9 

Cell contents: 

Number of atoms:  12 
Number of atom types:  3 
Chemical composition:  0 

Atomic positions (theoretical):

Hf:  0.8750  0.1250  0.7500 
Si:  0.3750  0.6250  0.7500 
O:  0.2582  0.1919  0.0663 
O:  0.6257  0.1919  0.4337 
Hf:  0.1250  0.8750  0.2500 
Si:  0.6250  0.3750  0.2500 
O:  0.1919  0.6257  0.9337 
O:  0.1919  0.2582  0.5663 
O:  0.3743  0.8081  0.5663 
O:  0.7418  0.8081  0.9337 
O:  0.8081  0.7418  0.4337 
O:  0.8081  0.3743  0.0663 
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
B1u
130
130
130
130
5
B1g
168
168
168
168
1.706e+39
1.7
1.280e+39
1.3
2.986e+39
3.1
6
Eg
172
172
172
172
8.394e+37
0.1
1.154e+38
0.1
1.994e+38
0.2
7
Eg
172
172
172
172
8.394e+37
0.1
1.154e+38
0.1
1.994e+38
0.2
8
Eg
219
219
219
219
4.615e+39
4.7
6.345e+39
6.5
1.096e+40
11.2
9
Eg
219
219
219
219
4.615e+39
4.7
6.345e+39
6.5
1.096e+40
11.2
10
A2g
248
248
248
248
11
B2g
256
256
256
256
2.008e+38
0.2
2.761e+38
0.3
4.768e+38
0.5
12
Eu
277
277
277
277
13
Eu
277
327
327
277
14
A2u
327
334
334
393
15
Eg
393
393
393
393
2.083e+40
21.3
2.864e+40
29.3
4.947e+40
50.7
16
Eg
393
393
393
402
2.083e+40
21.3
2.864e+40
29.3
4.947e+40
50.7
17
A1u
402
402
402
423
18
Eu
423
423
423
423
19
Eu
423
427
427
427
20
B1g
427
433
433
431
2.513e+39
2.6
1.885e+39
1.9
4.398e+39
4.5
21
Eu
434
434
434
434
22
Eu
434
475
475
434
23
A1g
482
482
482
482
4.231e+40
43.3
2.130e+40
21.8
6.361e+40
65.2
24
Eg
549
549
549
549
3.510e+37
0.0
4.826e+37
0.0
8.336e+37
0.1
25
Eg
549
549
549
549
3.510e+37
0.0
4.826e+37
0.0
8.336e+37
0.1
26
B2u
591
591
591
591
27
A2u
625
625
625
674
28
B1g
674
674
674
685
1.067e+39
1.1
8.000e+38
0.8
1.867e+39
1.9
29
Eu
896
896
896
896
30
Eu
896
963
963
896
31
Eg
963
963
963
963
6.820e+38
0.7
9.378e+38
1.0
1.620e+39
1.7
32
Eg
963
971
971
963
6.820e+38
0.7
9.378e+38
1.0
1.620e+39
1.7
33
B2u
971
1002
1002
971
34
A1g
1002
1010
1010
1002
5.512e+40
56.5
2.644e+38
0.3
5.539e+40
56.7
35
A2u
1010
1045
1045
1049
36
B1g
1049
1049
1049
1119
5.578e+40
57.1
4.184e+40
42.9
9.762e+40
100.0
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.