- PARALAURIONITE - PbClOH

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:	12		C2/m
Lattice parameters (Å):	10.8650	4.0060		7.2330
Angles (°):	90.0	117.2		90.0

Symmetry (theoretical):

Space group:	12		C2/m
Lattice parameters (Å):	5.6609	5.6609		7.0516
Angles (°):	64.9	115.1		139.5

Cell contents:

Number of atoms:	8
Number of atom types:	4
Chemical composition:	0

Atomic positions (theoretical):

Pb:	0.1687	0.8313	0.2365
Cl:	0.4308	0.5692	0.1904
O:	0.2002	0.7998	0.5905
H:	0.1188	0.8812	0.6204
Pb:	0.8313	0.1687	0.7635
Cl:	0.5692	0.4308	0.8096
O:	0.7998	0.2002	0.4095
H:	0.8812	0.1188	0.3796

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	45	45	45	45	3.503e+40 5.7	3.639e+40 5.9	7.143e+40 11.6
5	Bg	56	56	56	56	5.789e+40 9.4	6.338e+40 10.3	1.213e+41 19.7
6	Bu	77	80	77	80
7	Au	80	80	84	84
8	Ag	84	84	104	104	9.642e+40 15.7	9.212e+40 15.0	1.885e+41 30.7
9	Bg	104	104	112	109	2.513e+41 40.9	3.638e+41 59.1	6.151e+41 100.0
10	Ag	112	112	120	112	1.649e+41 26.8	2.258e+40 3.7	1.875e+41 30.5
11	Bu	120	141	141	138
12	Ag	141	210	153	141	2.467e+41 40.1	1.941e+41 31.6	4.408e+41 71.7
13	Au	251	251	292	251
14	Bu	292	293	293	293
15	Bg	293	296	296	294	2.625e+40 4.3	4.306e+40 7.0	6.930e+40 11.3
16	Ag	296	298	297	296	1.301e+41 21.2	2.907e+40 4.7	1.592e+41 25.9
17	Bu	320	324	320	339
18	Ag	339	339	339	367	1.165e+41 18.9	3.369e+40 5.5	1.501e+41 24.4
19	Bg	533	533	533	533	7.183e+40 11.7	1.106e+41 18.0	1.824e+41 29.7
20	Au	560	560	631	560
21	Bu	679	679	679	704
22	Ag	765	765	765	765	6.291e+40 10.2	4.741e+40 7.7	1.103e+41 17.9
23	Ag	3503	3503	3503	3503	4.279e+41 69.6	1.721e+40 2.8	4.451e+41 72.4
24	Bu	3507	3515	3507	3508

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥