- DIAMOND (4H) - 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):
Angles (°):	90	90		120

Symmetry (theoretical):

Space group:	194		P6_3/mmc
Lattice parameters (Å):	2.4805	2.4805		8.1841
Angles (°):	90	90		120

Cell contents:

Number of atoms:	8
Number of atom types:	1
Chemical composition:	0

Atomic positions (theoretical):

C:	1.0000	1.0000	0.9977
C:	1.0000	1.0000	0.1866
C:	0.3333	0.6667	0.2492
C:	0.3333	0.6667	0.4351
C:	0.6667	0.3333	0.4977
C:	0.6667	0.3333	0.6866
C:	0.3333	0.6667	0.7492
C:	0.3333	0.6667	0.9351

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:

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 ∥

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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	E2u	397	397	397	397
5	E2u	397	397	397	397
6	E2g	416	416	416	416	6.053e+37 0.0	8.242e+37 0.0	1.429e+38 0.0
7	E2g	416	416	416	416	6.053e+37 0.0	4.620e+37 0.0	1.067e+38 0.0
8	E1g	545	545	545	545	1.714e+38 0.0	2.356e+38 0.0	4.070e+38 0.1
9	E1g	545	545	545	545	1.714e+38 0.0	2.356e+38 0.0	4.070e+38 0.1
10	B1g	711	711	711	711
11	B2u	721	721	721	721
12	A1g	1076	1076	1076	1076	2.807e+40 5.7	3.841e+39 0.8	3.191e+40 6.5
13	E1u	1232	1232	1232	1232
14	E1u	1232	1232	1232	1232
15	A2u	1269	1269	1269	1269
16	E2g	1269	1269	1269	1269	1.112e+41 22.7	1.015e+41 20.7	2.126e+41 43.4
17	E2g	1269	1269	1269	1269	1.112e+41 22.7	1.348e+41 27.5	2.460e+41 50.2
18	E2u	1282	1282	1282	1282
19	E2u	1282	1282	1282	1282
20	B2u	1311	1311	1311	1311
21	A1g	1316	1316	1316	1316	2.917e+41 59.6	1.981e+41 40.4	4.897e+41 100.0
22	E1g	1332	1332	1332	1332	6.303e+40 12.9	8.620e+40 17.6	1.492e+41 30.5
23	E1g	1332	1332	1332	1332	6.303e+40 12.9	8.713e+40 17.8	1.502e+41 30.7
24	B1g	1340	1340	1340	1340

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

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