- HERZENBERGITE - SnS

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:	62		Pbnm
Lattice parameters (Å):	4.7104	10.2718		8.7476
Angles (°):	90	90		90

Symmetry (theoretical):

Space group:	62		Pbnm
Lattice parameters (Å):	4.2468	10.5425		3.8268
Angles (°):	90	90		90

Cell contents:

Number of atoms:	8
Number of atom types:	2
Chemical composition:	0

Atomic positions (theoretical):

Sn:	0.1448	0.1113	0.2500
S:	0.4513	0.8556	0.2500
Sn:	0.6448	0.3887	0.7500
S:	0.9513	0.6444	0.7500
Sn:	0.8552	0.8887	0.7500
S:	0.5487	0.1444	0.7500
Sn:	0.3552	0.6113	0.2500
S:	0.0487	0.3556	0.2500

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	A1g	49	49	49	49	1.272e+42 2.6	7.602e+41 1.5	2.032e+42 4.1
5	B2g	54	54	54	54	5.340e+41 1.1	7.343e+41 1.5	1.268e+42 2.6
6	Au	60	60	60	60
7	B2u	70	70	72	70
8	B3g	79	79	79	79	2.042e+42 4.1	2.807e+42 5.6	4.849e+42 9.8
9	B1g	91	91	91	91
10	A1g	96	96	96	96	2.349e+42 4.7	1.721e+42 3.5	4.069e+42 8.2
11	B1g	100	100	100	100	1.716e+41 0.3	2.359e+41 0.5	4.075e+41 0.8
12	B3u	118	123	118	118
13	B2u	173	173	175	173
14	B1u	175	175	194	194
15	B2g	194	194	207	207	2.093e+43 42.1	2.877e+43 57.9	4.970e+43 100.0
16	B3u	207	216	216	216
17	Au	216	217	217	217
18	A1g	217	223	223	223	4.678e+43 94.1	2.184e+42 4.4	4.896e+43 98.5
19	B3g	223	235	235	236	1.029e+40 0.0	1.414e+40 0.0	2.443e+40 0.0
20	B2u	236	236	244	244
21	A1g	244	244	245	245	3.837e+41 0.8	1.806e+41 0.4	5.642e+41 1.1
22	B3u	245	262	262	262
23	B1g	262	283	283	272	9.206e+41 1.9	1.266e+42 2.5	2.186e+42 4.4
24	B1g	283	301	360	283	3.876e+41 0.8	5.330e+41 1.1	9.206e+41 1.9

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥