-    DIAMOND (2H)     -    C

 

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:  194  P6_3/mmc 
Lattice parameters (Å):  0.0000  47.6260  47.6260 
Angles (°):  90  90  120 

Symmetry (theoretical): 

Space group:  194  P6_3/mmc 
Lattice parameters (Å):  2.4907  2.4907  4.1479 
Angles (°):  90  90  120 

Cell contents: 

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

Atomic positions (theoretical):

C:  0.3333  0.6667  0.4372 
C:  0.6667  0.3333  0.9372 
C:  0.6667  0.3333  0.5628 
C:  0.3333  0.6667  0.0628 
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
E2u
538
538
538
538
1.883e+38
0.1
1.597e+38
0.0
3.479e+38
0.1
5
E2u
538
538
538
538
1.927e+37
0.0
1.758e+37
0.0
3.685e+37
0.0
6
B2u
1093
1094
1094
1093
1.476e+37
0.0
2.416e+37
0.0
3.892e+37
0.0
7
E2g
1191
1191
1191
1191
5.234e+40
16.1
5.476e+40
16.9
1.071e+41
33.0
8
E2g
1191
1191
1191
1191
5.295e+40
16.3
5.701e+40
17.6
1.100e+41
33.9
9
B1g
1281
1281
1281
1281
3.094e+37
0.0
9.307e+36
0.0
4.025e+37
0.0
10
E1g
1308
1308
1308
1308
4.044e+40
12.5
4.421e+40
13.6
8.465e+40
26.1
11
E1g
1308
1308
1308
1308
4.043e+40
12.5
6.648e+40
20.5
1.069e+41
33.0
12
A1g
1313
1313
1313
1313
1.990e+41
61.3
1.254e+41
38.7
3.244e+41
100.0
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.