-    MONTROYDITE     -    HgO

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 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):  6.6697  5.2737  3.4419 
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:  0.1167  0.2500  0.2515 
O:  0.3664  0.2500  0.6103 
Hg:  0.3833  0.7500  0.7515 
O:  0.1336  0.7500  0.1103 
Hg:  0.8833  0.7500  0.7485 
O:  0.6336  0.7500  0.3897 
Hg:  0.6167  0.2500  0.2485 
O:  0.8664  0.2500  0.8897 
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
Au
36
36
36
36
5.052e+40
0.2
1.644e+40
0.1
6.696e+40
0.2
5
A1g
43
43
43
43
6.605e+39
0.0
9.082e+39
0.0
1.569e+40
0.1
6
B2g
55
59
55
55
7
B3u
59
61
59
59
2.594e+40
0.1
4.753e+39
0.0
3.069e+40
0.1
8
A1g
63
63
63
63
9
B3g
71
71
71
71
6.153e+38
0.0
8.460e+38
0.0
1.461e+39
0.0
10
Au
90
90
90
90
4.696e+38
0.0
6.457e+38
0.0
1.115e+39
0.0
11
B1g
134
134
134
134
7.949e+39
0.0
1.093e+40
0.0
1.888e+40
0.1
12
B3g
137
137
137
141
13
B2u
141
141
145
145
14
B2g
145
145
145
145
8.069e+40
0.3
1.110e+41
0.4
1.916e+41
0.6
15
B1u
145
145
263
146
16
B1g
263
263
274
263
3.303e+40
0.1
4.542e+40
0.2
7.845e+40
0.3
17
A1g
316
316
316
316
2.998e+43
99.9
3.984e+40
0.1
3.002e+43
100.0
18
B3u
374
374
374
374
19
B1u
464
464
464
464
1.629e+40
0.1
2.240e+40
0.1
3.868e+40
0.1
20
B2g
464
464
464
512
8.570e+40
0.3
1.178e+41
0.4
2.035e+41
0.7
21
B2g
517
517
517
517
22
B1u
534
534
534
534
2.011e+42
6.7
2.766e+42
9.2
4.777e+42
15.9
23
B3u
553
566
553
553
24
A1g
566
625
566
566
2.246e+40
0.1
1.173e+38
0.0
2.257e+40
0.1
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.