-    FRESNOITE     -    Ba2TiSi2O8

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:  100  P4bm 
Lattice parameters (Å):  8.5200  8.5200  5.2100 
Angles (°):  90  90  90 

Symmetry (theoretical): 

Space group:  100  P4bm 
Lattice parameters (Å):  8.4458  8.4458  5.0746 
Angles (°):  90  90  90 

Cell contents: 

Number of atoms:  26 
Number of atom types:  4 
Chemical composition:  0 

Atomic positions (theoretical):

Ba:  0.3271  0.8271  0.0041 
Si:  0.1282  0.6282  0.5207 
Ti:  0.0000  0.0000  0.5452 
O:  0.0000  0.5000  0.6410 
O:  0.1255  0.6255  0.2096 
O:  0.2933  0.5771  0.6555 
O:  0.0000  0.0000  0.2104 
Ba:  0.1729  0.3271  0.0041 
Si:  0.3718  0.1282  0.5207 
O:  0.5000  0.0000  0.6410 
O:  0.3745  0.1255  0.2096 
O:  0.4229  0.2933  0.6555 
Ba:  0.8271  0.6729  0.0041 
Si:  0.6282  0.8718  0.5207 
Ti:  0.5000  0.5000  0.5452 
O:  0.6255  0.8745  0.2096 
O:  0.7933  0.9229  0.6555 
O:  0.5000  0.5000  0.2104 
Ba:  0.6729  0.1729  0.0041 
Si:  0.8718  0.3718  0.5207 
O:  0.8745  0.3745  0.2096 
O:  0.7067  0.4229  0.6555 
O:  0.0771  0.7933  0.6555 
O:  0.9229  0.2067  0.6555 
O:  0.5771  0.7067  0.6555 
O:  0.2067  0.0771  0.6555 
Atom type  X  Y  Z 

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
B1
46
46
46
46
4.973e+38
0.2
3.730e+38
0.2
8.702e+38
0.4
5
E
53
53
53
53
3.612e+39
1.5
4.966e+39
2.1
8.578e+39
3.6
6
E
53
73
73
53
3.612e+39
1.5
4.967e+39
2.1
8.579e+39
3.6
7
A2
78
78
78
78
8
E
84
84
84
84
6.676e+38
0.3
9.180e+38
0.4
1.586e+39
0.7
9
E
84
86
86
84
6.676e+38
0.3
9.180e+38
0.4
1.586e+39
0.7
10
B2
99
99
99
99
4.338e+38
0.2
5.965e+38
0.3
1.030e+39
0.4
11
A1
102
102
102
103
3.488e+39
1.5
3.107e+37
0.0
3.519e+39
1.5
12
A2
112
112
112
112
13
E
116
116
116
116
2.140e+39
0.9
2.942e+39
1.2
5.082e+39
2.1
14
E
116
116
116
116
2.140e+39
0.9
2.942e+39
1.2
5.082e+39
2.1
15
E
123
123
123
123
4.294e+37
0.0
5.904e+37
0.0
1.020e+38
0.0
16
E
123
128
128
123
4.294e+37
0.0
5.904e+37
0.0
1.020e+38
0.0
17
A1
142
142
142
152
9.609e+39
4.0
2.033e+39
0.9
1.164e+40
4.9
18
B2
152
152
152
154
3.435e+39
1.4
4.723e+39
2.0
8.157e+39
3.4
19
B2
154
154
154
160
4.081e+39
1.7
5.611e+39
2.4
9.692e+39
4.1
20
A2
160
160
160
167
21
E
167
167
167
167
1.329e+39
0.6
1.827e+39
0.8
3.155e+39
1.3
22
E
167
173
173
173
1.329e+39
0.6
1.827e+39
0.8
3.155e+39
1.3
23
B1
173
174
174
179
8.033e+39
3.4
6.025e+39
2.5
1.406e+40
5.9
24
E
186
186
186
186
1.904e+38
0.1
2.618e+38
0.1
4.523e+38
0.2
25
E
186
188
188
186
1.905e+38
0.1
2.619e+38
0.1
4.523e+38
0.2
26
E
195
195
195
195
7.333e+39
3.1
1.008e+40
4.2
1.742e+40
7.3
27
E
195
195
195
195
7.333e+39
3.1
1.008e+40
4.2
1.742e+40
7.3
28
E
219
219
219
219
6.684e+39
2.8
9.191e+39
3.9
1.588e+40
6.7
29
E
219
219
219
219
6.684e+39
2.8
9.191e+39
3.9
1.588e+40
6.7
30
A1
230
230
230
232
4.184e+38
0.2
1.136e+38
0.0
5.321e+38
0.2
31
A2
232
232
232
239
32
A1
257
257
257
262
4.668e+38
0.2
2.561e+38
0.1
7.229e+38
0.3
33
E
265
265
265
265
1.308e+40
5.5
1.799e+40
7.5
3.107e+40
13.0
34
E
265
271
271
265
1.308e+40
5.5
1.799e+40
7.5
3.107e+40
13.0
35
B2
277
277
277
277
5.158e+39
2.2
7.093e+39
3.0
1.225e+40
5.1
36
A1
281
281
281
282
2.671e+37
0.0
8.905e+36
0.0
3.562e+37
0.0
37
E
316
316
316
316
3.651e+39
1.5
5.020e+39
2.1
8.671e+39
3.6
38
E
316
317
317
316
3.651e+39
1.5
5.020e+39
2.1
8.671e+39
3.6
39
E
335
335
335
335
5.306e+37
0.0
7.295e+37
0.0
1.260e+38
0.1
40
E
335
336
336
335
5.306e+37
0.0
7.296e+37
0.0
1.260e+38
0.1
41
B1
343
343
343
343
9.678e+39
4.1
7.258e+39
3.0
1.694e+40
7.1
42
B1
371
371
371
371
1.477e+40
6.2
1.108e+40
4.6
2.585e+40
10.8
43
E
372
372
372
372
1.246e+39
0.5
1.714e+39
0.7
2.960e+39
1.2
44
E
372
376
376
372
1.246e+39
0.5
1.714e+39
0.7
2.960e+39
1.2
45
E
386
386
386
386
8.733e+39
3.7
1.201e+40
5.0
2.074e+40
8.7
46
E
386
403
403
386
8.733e+39
3.7
1.201e+40
5.0
2.074e+40
8.7
47
B2
403
441
441
403
2.110e+39
0.9
2.901e+39
1.2
5.010e+39
2.1
48
A2
441
445
445
441
49
B2
445
447
447
445
9.579e+36
0.0
1.317e+37
0.0
2.275e+37
0.0
50
E
461
461
461
461
1.072e+37
0.0
1.474e+37
0.0
2.546e+37
0.0
51
E
461
466
466
461
1.072e+37
0.0
1.474e+37
0.0
2.546e+37
0.0
52
A1
466
469
469
468
1.085e+40
4.6
1.037e+38
0.0
1.095e+40
4.6
53
B1
469
500
500
469
4.330e+39
1.8
3.247e+39
1.4
7.577e+39
3.2
54
A2
500
500
500
500
55
E
545
545
545
545
1.388e+39
0.6
1.909e+39
0.8
3.297e+39
1.4
56
E
545
546
546
545
1.388e+39
0.6
1.909e+39
0.8
3.297e+39
1.4
57
B2
565
565
565
565
1.936e+39
0.8
2.662e+39
1.1
4.598e+39
1.9
58
A1
576
576
576
580
4.617e+40
19.4
4.201e+37
0.0
4.621e+40
19.4
59
E
580
580
580
580
1.434e+39
0.6
1.971e+39
0.8
3.405e+39
1.4
60
E
580
585
585
596
1.434e+39
0.6
1.971e+39
0.8
3.405e+39
1.4
61
A1
659
659
659
662
1.552e+40
6.5
8.975e+36
0.0
1.553e+40
6.5
62
B2
668
668
668
668
7.496e+38
0.3
1.031e+39
0.4
1.780e+39
0.7
63
A2
859
859
859
859
64
A1
863
863
863
867
2.380e+41
99.9
2.743e+38
0.1
2.383e+41
100.0
65
E
867
867
867
867
6.900e+38
0.3
9.488e+38
0.4
1.639e+39
0.7
66
E
867
875
875
878
6.900e+38
0.3
9.488e+38
0.4
1.639e+39
0.7
67
B1
879
879
879
879
2.496e+40
10.5
1.872e+40
7.9
4.367e+40
18.3
68
E
904
904
904
904
1.187e+40
5.0
1.633e+40
6.9
2.820e+40
11.8
69
E
904
925
925
904
1.187e+40
5.0
1.633e+40
6.9
2.820e+40
11.8
70
B2
925
949
949
925
1.483e+39
0.6
2.039e+39
0.9
3.522e+39
1.5
71
A1
949
952
952
965
2.155e+40
9.0
2.509e+38
0.1
2.180e+40
9.2
72
E
967
967
967
967
2.483e+38
0.1
3.415e+38
0.1
5.898e+38
0.2
73
E
967
993
993
967
2.483e+38
0.1
3.415e+38
0.1
5.898e+38
0.2
74
B2
993
1006
1006
993
6.212e+39
2.6
8.542e+39
3.6
1.475e+40
6.2
75
E
1017
1017
1017
1017
1.493e+38
0.1
2.054e+38
0.1
3.547e+38
0.1
76
E
1017
1024
1024
1017
1.493e+38
0.1
2.054e+38
0.1
3.547e+38
0.1
77
A2
1032
1032
1032
1032
78
A1
1033
1033
1033
1083
9.011e+39
3.8
1.438e+38
0.1
9.155e+39
3.8
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.