-    MASSICOT     -    PbO

Theoretical atomic positions and lattice parameters at experimental volum from 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:  57  Pbcm 
Lattice parameters (Å):  5.8931  5.4904  4.7528 
Angles (°):  90.0  90.0  90.0 

Symmetry (theoretical): 

Space group:  57  Pbcm 
Lattice parameters (Å):  5.9648  5.5570  4.6393 
Angles (°):  90.0  90.0  90.0 

Cell contents: 

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

Atomic positions (theoretical):

Pb:  0.2267  0.9868  0.2500 
O:  0.8695  0.0969  0.2500 
Pb:  0.7733  0.0132  0.7500 
O:  0.1305  0.9031  0.7500 
Pb:  0.7733  0.4868  0.2500 
O:  0.1305  0.5969  0.2500 
Pb:  0.2267  0.5132  0.7500 
O:  0.8695  0.4031  0.7500 
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
B2u
55
55
57
55
5
B2g
59
59
59
59
7.896e+39
0.3
1.086e+40
0.4
1.875e+40
0.7
6
Au
65
65
65
65
7
B1g
70
70
70
70
4.620e+40
1.6
6.352e+40
2.2
1.097e+41
3.8
8
A1g
87
87
87
87
2.429e+41
8.5
1.059e+41
3.7
3.488e+41
12.2
9
B3g
88
88
88
88
1.586e+40
0.6
2.181e+40
0.8
3.768e+40
1.3
10
B1u
96
96
96
102
11
B1g
102
102
102
126
4.507e+38
0.0
6.197e+38
0.0
1.070e+39
0.0
12
B3u
126
126
126
142
13
A1g
142
142
142
233
2.820e+42
98.9
3.106e+40
1.1
2.851e+42
100.0
14
B2g
233
233
233
291
7.884e+40
2.8
1.084e+41
3.8
1.873e+41
6.6
15
B2u
291
291
298
298
16
A1g
298
298
306
306
1.312e+42
46.0
1.983e+41
7.0
1.510e+42
53.0
17
Au
306
306
316
322
18
B1g
322
322
322
354
9.371e+39
0.3
1.289e+40
0.5
2.226e+40
0.8
19
B2u
354
354
356
356
20
B3u
356
360
362
362
21
B3g
362
362
399
390
5.367e+39
0.2
7.380e+39
0.3
1.275e+40
0.4
22
A1g
399
399
427
399
1.151e+41
4.0
2.271e+40
0.8
1.378e+41
4.8
23
B1g
427
427
438
427
8.057e+40
2.8
1.108e+41
3.9
1.914e+41
6.7
24
B3u
438
518
470
438
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.