- ARGUTITE - GeO₂

Experimental structure 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:	136		P4_2/mnm
Lattice parameters (Å):	4.3966	4.3966		2.8626
Angles (°):	90.0	90.0		90.0

Symmetry (theoretical):

Space group:	136		P4_2/mnm
Lattice parameters (Å):	4.3966	4.3966		2.8626
Angles (°):	90.0	90.0		90.0

Cell contents:

Number of atoms:	6
Number of atom types:	2
Chemical composition:	0

Atomic positions (theoretical):

Ge:	0.0000	0.0000	0.0000
O:	0.3063	0.3063	0.0000
Ge:	0.5000	0.5000	0.5000
O:	0.1937	0.8063	0.5000
O:	0.6937	0.6937	0.0000
O:	0.8063	0.1937	0.5000

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 ∥

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	B1g	194	194	194	194	1.229e+39 0.9	9.218e+38 0.7	2.151e+39 1.6
5	B1u	200	200	200	200
6	E1u	293	293	293	293
7	E1u	293	339	339	293
8	E1u	341	341	341	341
9	E1u	341	447	447	341
10	A2u	447	460	460	460
11	A2g	460	463	463	484
12	E1g	484	484	484	484	3.511e+38 0.3	3.730e+38 0.3	7.241e+38 0.5
13	E1g	484	484	484	594	3.511e+38 0.3	5.925e+38 0.4	9.435e+38 0.7
14	E1u	594	594	594	594
15	E1u	594	600	600	600
16	B1u	600	641	641	641
17	A1g	641	763	763	742	1.385e+41 100.0	1.134e+36 0.0	1.385e+41 100.0
18	B2g	797	797	797	797	6.680e+39 4.8	9.185e+39 6.6	1.587e+40 11.5

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥