- ERNIGGLIITE - SnTl₂As₂S₆

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 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:	147		P-3
Lattice parameters (Å):	6.6800	6.6800		7.1640
Angles (°):	90	90		120

Symmetry (theoretical):

Space group:	147		P-3
Lattice parameters (Å):	6.4641	6.4641		6.5197
Angles (°):	90	90		120

Cell contents:

Number of atoms:	11
Number of atom types:	3
Chemical composition:	0

Atomic positions (theoretical):

Sn:	0.0000	0.0000	0.0000
Tl:	0.3333	0.6667	0.4074
As:	0.3333	0.6667	0.9360
:	0.2430	0.3336	0.7539
:	0.0906	0.7570	0.7539
:	0.6664	0.9094	0.7539
Tl:	0.6667	0.3333	0.5926
As:	0.6667	0.3333	0.0640
:	0.7570	0.6664	0.2461
:	0.9094	0.2430	0.2461
:	0.3336	0.0906	0.2461

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	Ag	40	40	40	40	2.137e+42 2.1	1.883e+39 0.0	2.138e+42 2.1
5	Eg	41	41	41	41	3.126e+41 0.3	4.966e+41 0.5	8.092e+41 0.8
6	Eg	41	41	41	41	3.126e+41 0.3	2.632e+41 0.3	5.758e+41 0.6
7	Eu	52	52	52	52
8	Eu	52	54	54	52
9	Eg	74	74	74	74	1.500e+42 1.5	2.179e+42 2.2	3.679e+42 3.7
10	Eg	74	74	74	74	1.500e+42 1.5	1.206e+42 1.2	2.706e+42 2.7
11	Au	77	77	77	89
12	Ag	98	98	98	98	2.965e+41 0.3	4.412e+40 0.0	3.406e+41 0.3
13	Au	111	111	111	111
14	Eu	111	111	111	111
15	Eu	111	117	117	111
16	Ag	132	132	132	132	2.815e+43 28.1	1.492e+41 0.1	2.830e+43 28.3
17	Au	142	142	142	145
18	Eu	145	145	145	145
19	Eu	145	150	150	146
20	Eg	150	150	150	150	2.778e+42 2.8	3.711e+42 3.7	6.489e+42 6.5
21	Eg	150	164	164	150	2.778e+42 2.8	2.292e+42 2.3	5.070e+42 5.1
22	Eg	242	242	242	242	7.569e+41 0.8	8.023e+41 0.8	1.559e+42 1.6
23	Eg	242	242	242	242	7.569e+41 0.8	7.962e+41 0.8	1.553e+42 1.6
24	Eu	270	270	270	270
25	Eu	270	286	286	270
26	Ag	296	296	296	296	9.742e+43 97.4	2.649e+42 2.6	1.001e+44 100.0
27	Au	313	313	313	318
28	Eg	318	318	318	318	8.318e+41 0.8	1.102e+42 1.1	1.933e+42 1.9
29	Eg	318	318	318	320	8.318e+41 0.8	8.528e+41 0.9	1.685e+42 1.7
30	Eu	320	320	320	320
31	Eu	320	338	338	334
32	Ag	372	372	372	372	5.679e+42 5.7	6.513e+40 0.1	5.745e+42 5.7
33	Au	376	376	376	385

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥