-    MONTROYDITE     -    HgO

Theoretical atomic positions and lattice parameters at experimental volum from RRUFFentry#R070235 

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):  6.6060  5.5020  3.5100 
Angles (°):  90.0  90.0  90.0 

Symmetry (theoretical): 

Space group:  62  Pnma 
Lattice parameters (Å):  6.6668  5.4291  3.5247 
Angles (°):  90.0  90.0  90.0 

Cell contents: 

Number of atoms:  8 
Number of atom types:  2 
Chemical composition:  0 

Atomic positions (theoretical):

Hg:  0.1169  0.2500  0.2472 
O:  0.3653  0.2500  0.5971 
Hg:  0.3831  0.7500  0.7472 
O:  0.1347  0.7500  0.0971 
Hg:  0.8831  0.7500  0.7528 
O:  0.6347  0.7500  0.4029 
Hg:  0.6169  0.2500  0.2528 
O:  0.8653  0.2500  0.9029 
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
A1g
35
35
35
35
2.191e+40
0.1
7.597e+39
0.0
2.951e+40
0.2
5
B2g
41
41
41
41
1.852e+39
0.0
2.546e+39
0.0
4.398e+39
0.0
6
B3u
54
58
54
54
7
A1g
58
59
58
58
7.110e+39
0.0
3.340e+39
0.0
1.045e+40
0.1
8
Au
60
60
60
60
9
B3g
66
66
66
66
2.454e+40
0.1
3.374e+40
0.2
5.828e+40
0.3
10
B1g
78
78
78
78
1.634e+39
0.0
2.246e+39
0.0
3.880e+39
0.0
11
Au
108
108
108
108
12
B3g
118
118
118
118
1.440e+41
0.8
1.979e+41
1.1
3.419e+41
1.9
13
B2g
134
134
134
134
4.300e+39
0.0
5.912e+39
0.0
1.021e+40
0.1
14
B2u
137
137
138
137
15
B1u
138
138
245
145
16
B1g
245
245
261
245
2.506e+40
0.1
3.446e+40
0.2
5.952e+40
0.3
17
A1g
335
335
335
335
1.837e+43
99.7
5.939e+40
0.3
1.843e+43
100.0
18
B3u
381
381
381
381
19
B1u
475
475
475
476
20
B2g
476
476
476
519
3.961e+40
0.2
5.446e+40
0.3
9.407e+40
0.5
21
B1u
529
529
529
529
22
B2g
543
543
543
543
1.311e+42
7.1
1.802e+42
9.8
3.113e+42
16.9
23
B3u
566
576
566
566
24
A1g
576
638
576
576
8.566e+39
0.0
1.857e+38
0.0
8.752e+39
0.0
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.