-    OLIVINE-Ge     -    Mg2GeO4

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  1.0000  0.0000 
Mg:  0.9929  0.2753  0.2500 
Ge:  0.4356  0.0949  0.2500 
O:  0.7868  0.0919  0.2500 
O:  0.2277  0.4406  0.2500 
O:  0.2668  0.1650  0.0221 
Mg:  0.5000  0.5000  0.0000 
Mg:  0.4929  0.2247  0.7500 
Ge:  0.9356  0.4051  0.7500 
O:  0.2868  0.4081  0.7500 
O:  0.7277  0.0594  0.7500 
O:  0.7668  0.3350  0.9779 
Mg:  0.0000  1.0000  0.5000 
Mg:  0.0071  0.7247  0.7500 
Ge:  0.5644  0.9051  0.7500 
O:  0.2132  0.9081  0.7500 
O:  0.7723  0.5594  0.7500 
O:  0.7332  0.8350  0.5221 
Mg:  0.5000  0.5000  0.5000 
Mg:  0.5071  0.7753  0.2500 
Ge:  0.0644  0.5949  0.2500 
O:  0.7132  0.5919  0.2500 
O:  0.2723  0.9406  0.2500 
O:  0.2332  0.6650  0.4779 
O:  0.7332  0.8350  0.9779 
O:  0.2332  0.6650  0.0221 
O:  0.2668  0.1650  0.4779 
O:  0.7668  0.3350  0.5221 
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
83
83
83
83
5
B2u
121
121
121
121
6
B3g
142
142
142
142
9.328e+36
0.0
1.283e+37
0.0
2.215e+37
0.0
7
B2g
146
146
146
146
6.802e+37
0.0
9.353e+37
0.0
1.616e+38
0.1
8
Ag
152
152
152
152
1.792e+39
0.7
3.446e+37
0.0
1.826e+39
0.7
9
Au
164
164
164
164
10
B3u
166
166
166
166
11
B1g
168
168
168
168
1.396e+37
0.0
1.919e+37
0.0
3.315e+37
0.0
12
Ag
169
169
169
169
1.955e+39
0.8
4.844e+37
0.0
2.004e+39
0.8
13
B1u
179
179
179
180
14
B1g
209
209
209
209
7.685e+37
0.0
1.057e+38
0.0
1.825e+38
0.1
15
B2g
214
214
214
214
4.527e+37
0.0
6.224e+37
0.0
1.075e+38
0.0
16
B1u
238
238
238
238
17
B1u
238
238
238
238
18
B3g
241
241
241
241
2.789e+38
0.1
3.835e+38
0.2
6.624e+38
0.3
19
B2u
243
243
243
243
20
B2u
274
274
276
274
21
B1u
276
276
280
277
22
Au
280
280
282
280
23
B1u
282
282
282
285
24
Ag
288
288
288
288
4.081e+39
1.6
3.987e+38
0.2
4.479e+39
1.8
25
B2g
290
290
290
290
7.845e+37
0.0
1.079e+38
0.0
1.863e+38
0.1
26
B1g
291
291
291
291
7.848e+37
0.0
1.079e+38
0.0
1.864e+38
0.1
27
B3u
292
294
292
292
28
B1u
298
298
298
299
29
B3u
299
299
299
305
30
Ag
308
308
308
308
7.747e+38
0.3
5.541e+38
0.2
1.329e+39
0.5
31
B3g
316
316
316
316
3.673e+37
0.0
5.050e+37
0.0
8.723e+37
0.0
32
Au
333
333
333
333
33
B1g
336
336
336
336
1.798e+38
0.1
2.472e+38
0.1
4.269e+38
0.2
34
Ag
353
353
353
353
1.938e+39
0.8
1.396e+39
0.5
3.333e+39
1.3
35
B2g
359
359
359
359
3.689e+37
0.0
5.073e+37
0.0
8.762e+37
0.0
36
B1g
361
361
361
361
1.745e+37
0.0
2.399e+37
0.0
4.143e+37
0.0
37
B1u
365
365
365
366
38
B3g
366
366
366
367
2.987e+39
1.2
4.107e+39
1.6
7.094e+39
2.8
39
Au
367
367
367
367
40
B2u
370
370
380
370
41
B2u
383
383
396
383
42
B3u
396
397
398
396
43
B2u
400
400
401
400
44
B3u
401
403
403
401
45
B3g
403
405
405
403
4.527e+38
0.2
6.225e+38
0.2
1.075e+39
0.4
46
B1u
405
417
417
417
47
Au
417
417
417
417
48
Ag
417
421
432
432
4.144e+39
1.6
1.257e+39
0.5
5.401e+39
2.1
49
B3u
432
432
432
432
50
B1g
432
435
435
435
7.160e+38
0.3
9.844e+38
0.4
1.700e+39
0.7
51
B2g
435
440
435
437
6.145e+38
0.2
8.449e+38
0.3
1.459e+39
0.6
52
B2u
440
445
442
440
53
Au
445
452
445
445
54
B1u
457
457
457
458
55
B2u
458
458
460
460
56
Ag
460
460
470
465
1.351e+39
0.5
7.744e+38
0.3
2.125e+39
0.8
57
B1u
470
470
470
470
58
B3u
470
471
474
474
59
Au
474
474
493
494
60
B2u
494
494
494
494
61
B3u
494
507
507
507
62
Ag
507
508
508
508
1.983e+40
7.8
7.954e+38
0.3
2.063e+40
8.1
63
B2g
508
510
510
510
8.609e+38
0.3
1.184e+39
0.5
2.045e+39
0.8
64
B3u
510
513
513
513
65
B1g
513
525
525
525
2.210e+38
0.1
3.038e+38
0.1
5.248e+38
0.2
66
B3g
525
530
529
530
1.219e+39
0.5
1.676e+39
0.7
2.895e+39
1.1
67
B2u
530
550
541
549
68
B1g
550
607
550
550
1.976e+38
0.1
2.717e+38
0.1
4.694e+38
0.2
69
Ag
683
683
683
683
6.155e+39
2.4
3.083e+39
1.2
9.238e+39
3.6
70
B1g
691
691
691
691
7.006e+39
2.8
9.633e+39
3.8
1.664e+40
6.5
71
B2g
708
708
708
708
9.401e+39
3.7
1.293e+40
5.1
2.233e+40
8.8
72
B1u
708
708
708
711
73
B2u
711
711
730
730
74
Au
730
730
731
731
75
B3g
731
731
766
766
6.004e+39
2.4
8.255e+39
3.2
1.426e+40
5.6
76
B3u
766
766
767
767
77
Ag
767
767
771
774
2.532e+41
99.5
1.274e+39
0.5
2.545e+41
100.0
78
B2u
774
774
779
779
79
B1g
779
779
785
785
5.326e+38
0.2
7.323e+38
0.3
1.265e+39
0.5
80
B3u
785
786
795
805
81
Ag
805
805
805
807
2.404e+40
9.4
1.371e+40
5.4
3.774e+40
14.8
82
B3u
807
809
807
809
83
B2u
809
812
812
812
84
B1g
812
881
816
812
1.430e+38
0.1
1.966e+38
0.1
3.397e+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.