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Theoretical atomic positions and lattice parameters at experimental volum from 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:  166  R-3m 
Lattice parameters (Å):  5.2487  5.2487  18.6735 
Angles (°):  90  90  120 

Symmetry (theoretical): 

Space group:  166  R-3m 
Lattice parameters (Å):  6.9527  6.9527  6.9527 
Angles (°):  44.21  44.21  44.21 

Cell contents: 

Number of atoms:  13 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Ca:  0.0000  0.0000  0.0000 
Ca:  0.2033  0.2033  0.2033 
P:  0.4058  0.4058  0.4058 
O:  0.3250  0.3250  0.3250 
O:  0.2734  0.7537  0.2734 
O:  0.7537  0.2734  0.2734 
O:  0.2734  0.2734  0.7537 
Ca:  0.7967  0.7967  0.7967 
P:  0.5942  0.5942  0.5942 
O:  0.6750  0.6750  0.6750 
O:  0.7266  0.2463  0.7266 
O:  0.2463  0.7266  0.7266 
O:  0.7266  0.7266  0.2463 
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
A2g
-58
-58
-58
-58
2
ac
0
0
0
0
3
ac
0
0
0
0
4
ac
0
0
0
0
5
Eu
35
35
35
35
6
Eu
35
64
64
35
7
A1u
114
114
114
114
8
Eu
130
130
130
130
9
Eu
130
157
157
130
10
Eg
157
157
157
157
1.387e+39
1.2
2.302e+39
2.0
3.689e+39
3.3
11
Eg
157
186
186
157
1.387e+39
1.2
1.560e+39
1.4
2.947e+39
2.6
12
Eg
186
186
186
186
2.286e+39
2.0
2.957e+39
2.6
5.242e+39
4.6
13
Eg
186
207
207
186
2.286e+39
2.0
1.741e+39
1.5
4.026e+39
3.6
14
A1g
207
217
217
207
8.552e+38
0.8
1.064e+38
0.1
9.616e+38
0.8
15
Eg
223
223
223
223
3.703e+37
0.0
3.948e+37
0.0
7.652e+37
0.1
16
Eg
223
223
223
223
3.703e+37
0.0
4.110e+37
0.0
7.813e+37
0.1
17
Eu
245
245
245
245
18
Eu
245
272
272
245
19
A2u
272
303
303
276
20
A2u
303
304
304
304
21
A1g
304
326
326
387
3.047e+39
2.7
1.526e+38
0.1
3.200e+39
2.8
22
Eg
396
396
396
396
1.038e+40
9.2
1.577e+40
13.9
2.615e+40
23.1
23
Eg
396
396
396
396
1.038e+40
9.2
1.378e+40
12.2
2.415e+40
21.3
24
Eu
447
447
447
447
25
Eu
447
448
448
447
26
Eu
540
540
540
540
27
Eu
540
551
551
540
28
Eg
551
551
551
551
2.361e+39
2.1
2.951e+39
2.6
5.311e+39
4.7
29
Eg
551
552
552
551
2.361e+39
2.1
1.822e+39
1.6
4.183e+39
3.7
30
A2u
552
556
556
593
31
A1g
620
620
620
620
3.107e+39
2.7
1.058e+39
0.9
4.165e+39
3.7
32
A2u
942
942
942
947
33
A1g
952
952
952
952
1.131e+41
99.9
1.268e+38
0.1
1.132e+41
100.0
34
Eg
982
982
982
982
6.350e+39
5.6
9.612e+39
8.5
1.596e+40
14.1
35
Eg
982
982
982
982
6.350e+39
5.6
5.052e+39
4.5
1.140e+40
10.1
36
Eu
992
992
992
992
37
Eu
992
1083
1083
992
38
A1g
1083
1088
1088
1083
1.709e+40
15.1
7.147e+39
6.3
2.424e+40
21.4
39
A2u
1089
1089
1089
1183
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.