-    OLIVINE-Ge     -    MgCaGeO4

The crystal structure is fully relaxed (both unit cell parameters and atomic positions under symmetry constraints) starting from forsterite structure, #w000188 

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  Pnma 
Lattice parameters (Å):       
Angles (°):       

Symmetry (theoretical): 

Space group:  62  Pnma 
Lattice parameters (Å):  4.9032  11.1533  6.3039 
Angles (°):  90  90  90 

Cell contents: 

Number of atoms:  28 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Mg:  0.0000  0.0000  0.0000 
Ca:  0.9877  0.2723  0.2500 
Ge:  0.4206  0.0774  0.2500 
O:  0.7669  0.0776  0.2500 
O:  0.2581  0.4426  0.2500 
O:  0.2658  0.1444  0.0343 
Mg:  0.5000  0.5000  0.0000 
Ca:  0.4877  0.2277  0.7500 
Ge:  0.9206  0.4226  0.7500 
O:  0.2669  0.4224  0.7500 
O:  0.7581  0.0574  0.7500 
O:  0.7658  0.3556  0.9657 
Mg:  0.0000  0.0000  0.5000 
Ca:  0.0123  0.7277  0.7500 
Ge:  0.5794  0.9226  0.7500 
O:  0.2331  0.9224  0.7500 
O:  0.7419  0.5574  0.7500 
O:  0.7342  0.8556  0.5343 
Mg:  0.5000  0.5000  0.5000 
Ca:  0.5123  0.7723  0.2500 
Ge:  0.0794  0.5774  0.2500 
O:  0.7331  0.5776  0.2500 
O:  0.2419  0.9426  0.2500 
O:  0.2342  0.6444  0.4657 
O:  0.7342  0.8556  0.9657 
O:  0.2342  0.6444  0.0343 
O:  0.2658  0.1444  0.4657 
O:  0.7658  0.3556  0.5343 
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.

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
Au
78
78
78
78
5
B2u
106
106
106
106
6
B2g
122
122
122
122
9.832e+37
0.0
1.352e+38
0.1
2.335e+38
0.1
7
Ag
124
124
124
124
1.709e+39
0.8
3.965e+38
0.2
2.105e+39
1.0
8
B1g
134
134
134
134
3.093e+37
0.0
4.252e+37
0.0
7.345e+37
0.0
9
Ag
146
146
146
146
4.821e+38
0.2
3.783e+37
0.0
5.199e+38
0.2
10
B3u
153
153
153
153
11
B3g
167
167
167
167
2.407e+37
0.0
3.310e+37
0.0
5.718e+37
0.0
12
Au
179
179
179
179
13
B1u
189
189
189
189
14
B1g
192
192
192
192
4.012e+37
0.0
5.516e+37
0.0
9.528e+37
0.0
15
B1u
200
200
200
205
16
B2u
205
205
207
207
17
B3u
207
208
207
209
18
Au
211
211
211
211
19
B2g
219
219
219
219
6.608e+36
0.0
9.087e+36
0.0
1.569e+37
0.0
20
Ag
225
225
225
225
4.197e+39
2.0
2.718e+37
0.0
4.225e+39
2.0
21
B3u
238
241
238
238
22
B1u
242
242
242
243
23
B1g
243
243
243
243
7.766e+36
0.0
1.068e+37
0.0
1.844e+37
0.0
24
B3u
250
251
250
250
25
B3g
252
252
252
252
6.634e+37
0.0
9.121e+37
0.0
1.575e+38
0.1
26
B2g
253
253
253
253
9.033e+37
0.0
1.242e+38
0.1
2.145e+38
0.1
27
B2u
257
257
257
257
28
Au
268
268
268
268
29
B3g
269
269
269
269
4.362e+37
0.0
5.998e+37
0.0
1.036e+38
0.0
30
Ag
280
280
280
280
1.777e+39
0.8
1.988e+38
0.1
1.976e+39
0.9
31
Ag
304
304
304
304
1.795e+39
0.8
7.014e+38
0.3
2.497e+39
1.2
32
B1g
305
305
305
305
5.043e+38
0.2
6.935e+38
0.3
1.198e+39
0.6
33
B2g
305
305
305
305
4.710e+38
0.2
6.477e+38
0.3
1.119e+39
0.5
34
B1u
312
312
312
313
35
B1g
313
313
313
313
1.277e+39
0.6
1.756e+39
0.8
3.034e+39
1.4
36
Au
316
316
316
316
37
B3g
317
317
317
317
5.622e+38
0.3
7.731e+38
0.4
1.335e+39
0.6
38
B2u
318
318
328
318
39
B3u
328
334
333
328
40
B2u
334
343
341
334
41
B1u
356
356
356
366
42
Au
371
371
371
371
43
B3u
374
378
374
374
44
B2u
378
381
382
378
45
B1u
382
382
384
382
46
Au
384
384
385
384
47
Ag
399
399
399
399
8.759e+38
0.4
7.748e+36
0.0
8.836e+38
0.4
48
B1g
401
401
401
401
3.563e+39
1.7
4.900e+39
2.3
8.463e+39
4.0
49
Au
402
402
402
402
50
B1u
403
403
403
405
51
B3g
405
405
405
416
3.705e+37
0.0
5.094e+37
0.0
8.799e+37
0.0
52
B2u
416
416
425
425
53
B2g
425
425
430
435
3.067e+39
1.4
4.217e+39
2.0
7.284e+39
3.4
54
B2u
435
435
437
437
55
B3u
437
445
445
444
56
Au
445
449
449
445
57
B1u
449
449
456
456
58
B3u
456
457
457
457
59
Ag
457
457
468
470
1.794e+39
0.8
1.194e+39
0.6
2.988e+39
1.4
60
B2u
470
470
476
476
61
B3u
476
485
485
485
62
B3u
485
488
487
488
63
B2g
488
488
488
488
5.902e+38
0.3
8.116e+38
0.4
1.402e+39
0.7
64
B2u
488
493
493
493
65
B1g
493
499
499
499
9.924e+37
0.0
1.365e+38
0.1
2.357e+38
0.1
66
Ag
499
500
500
500
1.862e+40
8.8
1.857e+39
0.9
2.048e+40
9.6
67
B3g
500
517
514
512
2.178e+38
0.1
2.994e+38
0.1
5.172e+38
0.2
68
B1g
517
583
517
517
4.230e+38
0.2
5.816e+38
0.3
1.005e+39
0.5
69
Ag
673
673
673
673
1.145e+40
5.4
5.451e+39
2.6
1.690e+40
7.9
70
B1g
677
677
677
677
3.522e+39
1.7
4.843e+39
2.3
8.366e+39
3.9
71
B2u
708
708
708
708
72
B2g
708
708
708
708
2.155e+39
1.0
2.964e+39
1.4
5.119e+39
2.4
73
B1u
708
708
719
719
74
Au
719
719
719
719
2.870e+39
1.3
3.946e+39
1.9
6.816e+39
3.2
75
B3g
719
719
754
754
3.915e+39
1.8
5.383e+39
2.5
9.298e+39
4.4
76
B3u
754
755
754
762
77
Ag
762
762
762
763
2.058e+41
96.8
6.825e+39
3.2
2.126e+41
100.0
78
B2u
763
763
767
767
79
B1g
767
767
777
777
1.450e+37
0.0
1.993e+37
0.0
3.443e+37
0.0
80
B3u
777
780
779
780
81
Ag
780
780
780
783
1.471e+40
6.9
9.316e+39
4.4
2.403e+40
11.3
82
B3u
783
785
783
785
83
B2u
785
790
790
790
84
B1g
790
843
796
797
5.576e+37
0.0
7.667e+37
0.0
1.324e+38
0.1
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.