-    ORPIMENT     -    As2S3

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/n 
Lattice parameters (Å):  11.4750  9.5770  4.2560 
Angles (°):  90  90.68  90 

Symmetry (theoretical): 

Space group:  14  P2_1/n 
Lattice parameters (Å):  9.8765  9.8178  4.3838 
Angles (°):  90  90.01  90 

Cell contents: 

Number of atoms:  20 
Number of atom types:  2 
Chemical composition:  0 

Atomic positions (theoretical):

As:  0.2470  0.1230  0.7903 
As:  0.3968  0.3708  0.2997 
S:  0.4084  0.1429  0.4320 
S:  0.2320  0.3545  0.9379 
S:  0.0708  0.1636  0.4658 
As:  0.2530  0.6230  0.7097 
As:  0.1032  0.8708  0.2003 
S:  0.0916  0.6429  0.0680 
S:  0.2680  0.8545  0.5621 
S:  0.4292  0.6636  0.0342 
As:  0.7530  0.8770  0.2097 
As:  0.6032  0.6292  0.7003 
S:  0.5916  0.8571  0.5680 
S:  0.7680  0.6455  0.0621 
S:  0.9292  0.8364  0.5342 
As:  0.7470  0.3770  0.2903 
As:  0.8968  0.1292  0.7997 
S:  0.9084  0.3571  0.9320 
S:  0.7320  0.1455  0.4379 
S:  0.5708  0.3364  0.9658 
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
Ag
20
20
20
20
5
Ag
37
37
37
37
7.537e+41
5.7
4.889e+41
3.7
1.243e+42
9.4
6
Ag
62
62
62
62
7.313e+41
5.6
2.810e+41
2.1
1.012e+42
7.7
7
Au
66
66
67
66
8
Bg
72
72
72
72
2.605e+40
0.2
3.869e+40
0.3
6.474e+40
0.5
9
Au
80
80
90
80
10
Bg
90
90
90
90
6.563e+40
0.5
8.110e+40
0.6
1.467e+41
1.1
11
Bu
90
91
91
91
12
Au
92
92
93
92
13
Bu
93
95
96
96
14
Ag
96
96
98
96
1.609e+42
12.2
3.340e+41
2.5
1.943e+42
14.7
15
Bg
98
98
100
98
5.810e+40
0.4
6.623e+40
0.5
1.243e+41
0.9
16
Bg
112
112
112
112
9.944e+39
0.1
1.066e+40
0.1
2.060e+40
0.2
17
Au
122
122
127
122
18
Ag
127
127
127
127
1.291e+42
9.8
1.896e+41
1.4
1.480e+42
11.2
19
Bg
135
135
135
135
6.377e+39
0.0
8.370e+39
0.1
1.475e+40
0.1
20
Au
139
139
140
139
21
Ag
141
141
141
141
3.345e+41
2.5
6.149e+40
0.5
3.960e+41
3.0
22
Bu
143
144
143
145
23
Bg
146
146
146
146
2.131e+41
1.6
3.152e+41
2.4
5.283e+41
4.0
24
Au
148
148
148
148
25
Bu
153
155
153
156
26
Au
157
157
158
157
27
Ag
158
158
161
158
2.660e+41
2.0
3.165e+40
0.2
2.976e+41
2.3
28
Bu
161
161
161
161
29
Bg
161
162
163
163
1.453e+39
0.0
2.391e+39
0.0
3.844e+39
0.0
30
Ag
169
169
169
169
7.518e+41
5.7
1.619e+41
1.2
9.137e+41
6.9
31
Au
173
173
177
173
32
Bg
177
177
183
177
4.343e+41
3.3
7.124e+41
5.4
1.147e+42
8.7
33
Bu
183
183
184
185
34
Bu
190
192
190
192
35
Ag
192
194
192
195
3.519e+42
26.7
1.273e+42
9.7
4.791e+42
36.4
36
Bg
195
195
195
195
2.667e+40
0.2
2.864e+40
0.2
5.531e+40
0.4
37
Au
270
270
276
270
38
Ag
276
276
286
276
9.362e+42
71.1
3.811e+42
28.9
1.317e+43
100.0
39
Bu
293
298
293
293
40
Bg
298
299
298
298
4.892e+41
3.7
5.268e+41
4.0
1.016e+42
7.7
41
Ag
299
302
299
299
6.633e+42
50.4
1.834e+42
13.9
8.467e+42
64.3
42
Bu
302
306
302
306
43
Au
306
310
310
310
44
Bg
310
316
318
312
2.430e+41
1.8
2.818e+41
2.1
5.247e+41
4.0
45
Ag
318
318
319
318
1.376e+42
10.4
6.785e+41
5.2
2.055e+42
15.6
46
Au
321
321
325
321
47
Bu
325
326
330
330
48
Bg
330
330
338
335
6.793e+41
5.2
1.062e+42
8.1
1.741e+42
13.2
49
Ag
338
338
339
338
9.552e+42
72.5
3.614e+41
2.7
9.913e+42
75.3
50
Au
340
340
340
340
51
Bg
340
340
343
340
1.027e+41
0.8
1.477e+41
1.1
2.504e+41
1.9
52
Bu
348
350
348
351
53
Bu
360
361
360
362
54
Ag
362
362
362
363
4.004e+41
3.0
3.752e+40
0.3
4.379e+41
3.3
55
Au
363
363
365
366
56
Bg
366
366
366
366
3.502e+40
0.3
3.913e+40
0.3
7.416e+40
0.6
57
Ag
366
366
366
367
3.247e+42
24.6
5.843e+41
4.4
3.831e+42
29.1
58
Au
370
370
370
370
59
Bu
370
370
370
371
60
Bg
371
371
371
373
5.706e+40
0.4
7.955e+40
0.6
1.366e+41
1.0
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.