-    PORTLANDITE     -    Ca(OH)2

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:  164  P-3m1 
Lattice parameters (Å):  3.5925  3.5925  4.9050 
Angles (°):  90.0  90.0  120.0 

Symmetry (theoretical): 

Space group:  164  P-3m1 
Lattice parameters (Å):  3.6059  3.6059  4.8685 
Angles (°):  90.0  90.0  120.0 

Cell contents: 

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

Atomic positions (theoretical):

Ca:  0.0000  0.0000  0.0000 
O:  0.3333  0.6667  0.2365 
H:  0.3333  0.6667  0.4361 
O:  0.6667  0.3333  0.7635 
H:  0.6667  0.3333  0.5639 
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
Eg
263
263
263
263
1.925e+39
0.6
2.910e+39
0.9
4.836e+39
1.5
5
Eg
263
263
263
263
1.925e+39
0.6
2.494e+39
0.8
4.419e+39
1.4
6
Eu
313
313
313
313
7
Eu
313
343
343
313
8
Eu
345
345
345
345
9
Eu
345
358
358
345
10
A1g
358
362
362
358
2.307e+40
7.2
4.401e+38
0.1
2.351e+40
7.4
11
A2u
362
603
603
465
12
Eg
695
695
695
695
1.655e+40
5.2
2.468e+40
7.8
4.123e+40
12.9
13
Eg
695
695
695
695
1.655e+40
5.2
1.668e+40
5.2
3.323e+40
10.4
14
A1g
3582
3582
3582
3582
3.024e+41
95.0
1.602e+40
5.0
3.184e+41
100.0
15
A2u
3610
3610
3610
3625
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.