-    CLINOENSTATITE     -    Mg2Si2O6

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:  14  P2_1/c 
Lattice parameters (Å):  9.6200  8.8250  5.1880 
Angles (°):  90.0  71.7  90.0 

Symmetry (theoretical): 

Space group:  14  P2_1/c 
Lattice parameters (Å):  9.4479  8.6502  5.0862 
Angles (°):  90.0  72.0  90.0 

Cell contents: 

Number of atoms:  40 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Mg:  0.2485  0.3448  0.2139 
Mg:  0.2432  0.9862  0.2110 
Si:  0.4570  0.6580  0.2969 
Si:  0.0547  0.6624  0.2744 
O:  0.3653  0.1603  0.3117 
O:  0.1237  0.1613  0.1203 
O:  0.3767  0.4971  0.3193 
O:  0.1346  0.5169  0.1083 
O:  0.3929  0.7835  0.1210 
O:  0.1077  0.8099  0.0543 
Mg:  0.7515  0.8448  0.2861 
Mg:  0.7568  0.4862  0.2890 
Si:  0.5430  0.1580  0.2031 
Si:  0.9453  0.1624  0.2256 
O:  0.6347  0.6603  0.1883 
O:  0.8763  0.6613  0.3797 
O:  0.6233  0.9971  0.1807 
O:  0.8654  0.0169  0.3917 
O:  0.6071  0.2835  0.3790 
O:  0.8923  0.3099  0.4457 
Mg:  0.7515  0.6552  0.7861 
Mg:  0.7568  0.0138  0.7890 
Si:  0.5430  0.3420  0.7031 
Si:  0.9453  0.3376  0.7256 
O:  0.6347  0.8397  0.6883 
O:  0.8763  0.8387  0.8797 
O:  0.6233  0.5029  0.6807 
O:  0.8654  0.4831  0.8917 
O:  0.6071  0.2165  0.8790 
O:  0.8923  0.1901  0.9457 
Mg:  0.2485  0.1552  0.7139 
Mg:  0.2432  0.5138  0.7110 
Si:  0.4570  0.8420  0.7969 
Si:  0.0547  0.8376  0.7744 
O:  0.3653  0.3397  0.8117 
O:  0.1237  0.3387  0.6203 
O:  0.3767  0.0029  0.8193 
O:  0.1346  0.9831  0.6083 
O:  0.3929  0.7165  0.6210 
O:  0.1077  0.6901  0.5543 
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
Bu
126
126
126
126
5
Ag
128
128
128
128
4.754e+38
1.7
4.694e+38
1.6
9.449e+38
3.3
6
Ag
150
150
150
150
8.457e+38
2.9
8.641e+37
0.3
9.321e+38
3.2
7
Ag
155
155
155
155
8.929e+38
3.1
2.882e+37
0.1
9.218e+38
3.2
8
Bg
156
156
156
156
3.039e+38
1.1
3.453e+38
1.2
6.492e+38
2.3
9
Au
158
158
158
158
10
Bg
165
165
165
165
1.585e+37
0.1
1.805e+37
0.1
3.390e+37
0.1
11
Bg
195
195
195
195
4.814e+38
1.7
6.061e+38
2.1
1.088e+39
3.8
12
Ag
201
201
201
201
3.754e+38
1.3
2.282e+38
0.8
6.036e+38
2.1
13
Bg
203
203
203
203
4.903e+38
1.7
8.217e+38
2.9
1.312e+39
4.6
14
Bu
205
205
205
205
15
Ag
207
207
207
207
4.302e+38
1.5
2.137e+38
0.7
6.439e+38
2.2
16
Au
207
207
207
207
17
Ag
213
213
213
213
3.948e+38
1.4
2.804e+38
1.0
6.752e+38
2.3
18
Bu
221
221
221
221
19
Au
223
228
223
224
20
Bu
229
229
235
229
21
Ag
235
235
237
235
2.936e+38
1.0
5.692e+37
0.2
3.505e+38
1.2
22
Bg
238
238
238
238
2.822e+38
1.0
2.998e+38
1.0
5.820e+38
2.0
23
Au
244
244
244
244
24
Bu
248
248
249
248
25
Bg
249
249
253
249
6.733e+38
2.3
8.481e+38
2.9
1.521e+39
5.3
26
Ag
253
253
257
253
1.944e+39
6.8
6.013e+37
0.2
2.004e+39
7.0
27
Au
265
265
265
265
28
Ag
284
284
284
284
6.524e+38
2.3
3.099e+38
1.1
9.623e+38
3.3
29
Au
285
285
285
285
30
Bu
287
287
294
287
31
Bg
294
294
297
294
3.818e+37
0.1
5.250e+37
0.2
9.067e+37
0.3
32
Bu
298
298
300
298
33
Au
301
304
301
301
34
Bg
304
305
304
304
8.600e+37
0.3
1.375e+38
0.5
2.235e+38
0.8
35
Au
307
311
307
307
36
Ag
311
313
311
311
3.542e+38
1.2
2.529e+38
0.9
6.071e+38
2.1
37
Bu
321
321
323
321
38
Au
329
331
329
329
39
Bg
331
333
331
331
3.230e+37
0.1
4.819e+37
0.2
8.049e+37
0.3
40
Ag
333
333
333
333
8.336e+38
2.9
4.836e+38
1.7
1.317e+39
4.6
41
Au
342
345
342
342
42
Bg
345
347
345
345
2.249e+38
0.8
2.394e+38
0.8
4.642e+38
1.6
43
Ag
347
350
347
347
1.963e+39
6.8
3.826e+37
0.1
2.002e+39
7.0
44
Bg
350
353
350
350
4.764e+37
0.2
5.734e+37
0.2
1.050e+38
0.4
45
Bu
354
354
354
354
46
Au
354
363
358
355
47
Ag
363
363
363
363
1.637e+40
56.9
3.337e+38
1.2
1.670e+40
58.1
48
Bu
363
370
372
363
49
Au
374
375
374
374
50
Ag
375
376
375
375
3.005e+39
10.5
6.409e+38
2.2
3.646e+39
12.7
51
Bg
376
379
376
376
4.844e+38
1.7
5.363e+38
1.9
1.021e+39
3.5
52
Bu
379
395
379
379
53
Bg
395
396
395
395
4.024e+38
1.4
6.324e+38
2.2
1.035e+39
3.6
54
Bu
396
397
396
396
55
Bg
397
398
397
397
7.834e+37
0.3
8.924e+37
0.3
1.676e+38
0.6
56
Ag
416
416
416
416
2.135e+39
7.4
2.407e+38
0.8
2.376e+39
8.3
57
Bg
419
419
419
419
58
Bg
419
423
419
421
3.136e+37
0.1
5.196e+37
0.2
8.332e+37
0.3
59
Au
423
423
423
423
60
Bu
423
427
424
425
61
Ag
427
432
427
427
1.666e+38
0.6
1.392e+38
0.5
3.058e+38
1.1
62
Au
432
436
432
432
63
Bu
436
437
437
436
64
Ag
437
447
438
437
3.366e+39
11.7
4.049e+38
1.4
3.771e+39
13.1
65
Bg
447
450
447
447
1.389e+38
0.5
1.671e+38
0.6
3.060e+38
1.1
66
Ag
456
456
456
456
3.451e+38
1.2
3.993e+38
1.4
7.444e+38
2.6
67
Bu
458
458
464
458
68
Au
464
467
465
468
69
Bg
468
468
468
469
2.133e+38
0.7
3.592e+38
1.2
5.725e+38
2.0
70
Bu
469
469
471
475
71
Bu
477
477
481
477
72
Au
481
481
483
487
73
Bg
487
487
487
488
2.499e+38
0.9
3.604e+38
1.3
6.104e+38
2.1
74
Bu
489
489
506
489
75
Au
506
509
509
509
76
Ag
509
512
513
513
4.067e+38
1.4
1.181e+38
0.4
5.249e+38
1.8
77
Bu
513
513
523
523
78
Bg
523
523
524
524
4.827e+38
1.7
6.921e+38
2.4
1.175e+39
4.1
79
Ag
524
524
533
533
9.387e+38
3.3
5.815e+37
0.2
9.969e+38
3.5
80
Bg
533
533
535
534
1.622e+38
0.6
2.230e+38
0.8
3.852e+38
1.3
81
Au
535
536
536
536
82
Bu
536
542
542
542
83
Ag
542
545
553
545
1.053e+39
3.7
4.621e+37
0.2
1.099e+39
3.8
84
Ag
553
553
555
553
2.632e+38
0.9
3.211e+37
0.1
2.953e+38
1.0
85
Au
555
565
558
565
86
Bu
565
566
574
579
87
Bg
579
579
579
591
5.129e+38
1.8
8.627e+38
3.0
1.376e+39
4.8
88
Bg
591
591
591
619
1.534e+38
0.5
2.585e+38
0.9
4.119e+38
1.4
89
Au
641
654
641
643
90
Ag
660
660
660
660
1.789e+40
62.2
6.478e+37
0.2
1.795e+40
62.4
91
Au
675
675
675
682
92
Ag
682
682
682
682
2.115e+40
73.5
2.480e+38
0.9
2.140e+40
74.4
93
Bu
718
718
720
718
94
Bu
732
732
734
732
95
Bg
734
734
739
734
6.088e+36
0.0
6.472e+36
0.0
1.256e+37
0.0
96
Bg
752
752
752
752
6.029e+38
2.1
7.211e+38
2.5
1.324e+39
4.6
97
Au
831
832
831
832
98
Ag
832
834
832
861
9.243e+38
3.2
9.367e+38
3.3
1.861e+39
6.5
99
Bu
875
875
882
875
100
Bg
888
888
888
888
1.275e+38
0.4
1.887e+38
0.7
3.162e+38
1.1
101
Bu
890
890
901
890
102
Bg
901
901
907
901
1.712e+38
0.6
2.781e+38
1.0
4.494e+38
1.6
103
Bu
912
912
917
912
104
Ag
917
917
920
917
1.077e+39
3.7
6.063e+38
2.1
1.683e+39
5.9
105
Au
920
920
920
920
106
Bg
920
921
920
928
3.921e+36
0.0
5.391e+36
0.0
9.312e+36
0.0
107
Ag
928
928
928
929
2.201e+39
7.7
1.530e+38
0.5
2.354e+39
8.2
108
Au
930
991
930
979
109
Bu
995
995
1003
995
110
Au
1003
1007
1007
1007
111
Ag
1007
1010
1010
1014
2.571e+40
89.4
3.051e+39
10.6
2.876e+40
100.0
112
Bg
1014
1014
1014
1015
1.260e+38
0.4
1.471e+38
0.5
2.731e+38
0.9
113
Bu
1019
1019
1020
1019
114
Ag
1030
1030
1030
1030
1.701e+40
59.1
8.423e+38
2.9
1.785e+40
62.1
115
Ag
1041
1041
1041
1041
4.958e+39
17.2
3.638e+38
1.3
5.321e+39
18.5
116
Bg
1046
1046
1046
1046
8.097e+38
2.8
1.249e+39
4.3
2.059e+39
7.2
117
Au
1050
1057
1050
1057
118
Bg
1057
1069
1057
1069
4.568e+38
1.6
4.883e+38
1.7
9.451e+38
3.3
119
Bu
1069
1105
1139
1089
120
Au
1147
1151
1147
1150
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.