-    LUESHITE     -    NaNbO3

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:  62  Pbnm 
Lattice parameters (Å):  5.4043  5.4224  7.6510 
Angles (°):  90  90  90 

Symmetry (theoretical): 

Space group:  62  Pbnm 
Lattice parameters (Å):  5.3778  5.4906  7.6898 
Angles (°):  90  90  90 

Cell contents: 

Number of atoms:  20 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Na:  0.9917  0.0382  0.2500 
Nb:  0.5000  0.0000  0.0000 
O:  0.0853  0.4786  0.2500 
O:  0.7041  0.2940  0.0443 
Na:  0.4917  0.4618  0.7500 
Nb:  0.0000  0.5000  0.0000 
O:  0.5853  0.0214  0.7500 
O:  0.2041  0.2060  0.9557 
Na:  0.0083  0.9618  0.7500 
Nb:  0.5000  0.0000  0.5000 
O:  0.9147  0.5214  0.7500 
O:  0.2959  0.7060  0.5443 
Na:  0.5083  0.5382  0.2500 
Nb:  0.0000  0.5000  0.5000 
O:  0.4147  0.9786  0.2500 
O:  0.7959  0.7940  0.4557 
O:  0.2959  0.7060  0.9557 
O:  0.7959  0.7940  0.0443 
O:  0.7041  0.2940  0.4557 
O:  0.2041  0.2060  0.5443 
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
Au
94
94
94
94
5
B1u
96
96
96
99
6
A1g
119
119
119
119
2.892e+40
13.8
2.052e+40
9.8
4.944e+40
23.7
7
Au
120
120
120
120
8
B3u
139
141
139
139
9
B1g
141
144
141
141
2.275e+40
10.9
3.129e+40
15.0
5.404e+40
25.9
10
B2u
146
146
151
146
11
B1u
151
151
157
156
12
A1g
158
158
158
158
3.537e+40
16.9
6.492e+38
0.3
3.602e+40
17.2
13
Au
162
162
162
162
14
B1g
171
171
171
171
1.374e+40
6.6
1.889e+40
9.0
3.262e+40
15.6
15
B2g
172
172
172
172
8.406e+37
0.0
1.156e+38
0.1
1.996e+38
0.1
16
B2u
181
181
181
181
17
B3g
182
182
182
182
6.081e+39
2.9
8.361e+39
4.0
1.444e+40
6.9
18
B3u
189
189
189
189
19
B3g
194
194
194
194
4.718e+38
0.2
6.487e+38
0.3
1.121e+39
0.5
20
B1g
204
204
204
204
6.034e+36
0.0
8.297e+36
0.0
1.433e+37
0.0
21
B1g
205
205
205
213
7.741e+38
0.4
1.064e+39
0.5
1.838e+39
0.9
22
Au
213
213
213
218
23
B3u
218
220
218
220
24
B2u
220
227
227
227
25
A1g
227
239
230
239
1.415e+40
6.8
8.117e+39
3.9
2.227e+40
10.7
26
B3u
239
242
239
242
27
B2u
242
243
243
242
28
B1u
243
245
245
245
29
Au
245
267
262
270
30
B3u
270
271
270
271
31
B2u
271
280
280
280
32
A1g
280
311
308
311
1.709e+41
81.8
2.422e+39
1.2
1.733e+41
82.9
33
B2g
311
317
311
317
6.645e+37
0.0
9.137e+37
0.0
1.578e+38
0.1
34
B2u
317
320
320
320
35
A1g
320
326
341
341
2.086e+41
99.9
2.976e+38
0.1
2.089e+41
100.0
36
B3u
341
347
347
347
37
B3g
347
358
362
352
38
B1g
362
362
403
362
1.084e+37
0.0
1.491e+37
0.0
2.575e+37
0.0
39
B1g
403
403
407
403
5.533e+37
0.0
7.608e+37
0.0
1.314e+38
0.1
40
B2g
433
433
433
433
1.356e+39
0.6
1.865e+39
0.9
3.221e+39
1.5
41
Au
438
438
438
438
42
A1g
441
441
441
441
2.459e+40
11.8
1.560e+40
7.5
4.019e+40
19.2
43
B3u
445
446
445
445
44
B1u
446
450
446
450
45
B1g
450
468
450
471
7.230e+39
3.5
9.941e+39
4.8
1.717e+40
8.2
46
B3u
471
490
471
484
47
B2u
490
497
494
490
48
B2u
519
519
520
519
49
B3g
655
655
655
655
1.534e+40
7.3
2.109e+40
10.1
3.644e+40
17.4
50
B1u
656
656
656
657
51
B2g
659
659
659
659
3.403e+40
16.3
4.680e+40
22.4
8.083e+40
38.7
52
B2u
662
662
664
662
53
Au
664
664
677
664
54
Au
677
677
678
677
55
B1u
678
678
680
680
56
A1g
680
680
682
682
1.276e+40
6.1
9.431e+39
4.5
2.219e+40
10.6
57
B3u
682
918
918
918
58
B3g
918
939
940
938
1.275e+39
0.6
1.754e+39
0.8
3.029e+39
1.4
59
B1g
947
947
947
947
1.080e+38
0.1
1.485e+38
0.1
2.565e+38
0.1
60
B2g
976
976
976
976
3.231e+38
0.2
4.442e+38
0.2
7.673e+38
0.4
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.