- RORISITE - CaClF

Theoretical atomic positions and lattice parameters at experimental volum 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:	129		P4/nmm
Lattice parameters (Å):	2.0606	2.0606		3.6079
Angles (°):	90.0	90.0		90.0

Symmetry (theoretical):

Space group:	129		P4/nmm
Lattice parameters (Å):	3.9019	3.9019		6.7905
Angles (°):	90.0	90.0		90.0

Cell contents:

Number of atoms:	6
Number of atom types:	3
Chemical composition:	0

Atomic positions (theoretical):

Ca:	0.2500	0.2500	0.1952
Cl:	0.2500	0.2500	0.6435
F:	0.7500	0.2500	0.0000
Ca:	0.7500	0.7500	0.8048
Cl:	0.7500	0.7500	0.3565
F:	0.2500	0.7500	0.0000

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	Eu	129	129	129	129
5	Eu	129	149	149	129
6	Eg	149	149	149	149	9.271e+37 0.8	1.275e+38 1.1	2.202e+38 1.9
7	Eg	149	160	160	149	9.271e+37 0.8	1.275e+38 1.1	2.202e+38 1.9
8	A2u	160	164	164	173
9	Eg	173	173	173	173	2.914e+38 2.5	4.007e+38 3.4	6.921e+38 5.9
10	Eg	173	173	173	178	2.914e+38 2.5	4.007e+38 3.4	6.921e+38 5.9
11	A1g	178	178	178	222	8.554e+39 72.6	7.704e+38 6.5	9.325e+39 79.2
12	B1g	262	262	262	262	6.731e+39 57.1	5.048e+39 42.9	1.178e+40 100.0
13	A1g	263	263	263	263	4.228e+39 35.9	1.507e+38 1.3	4.379e+39 37.2
14	Eu	282	282	282	282
15	Eu	282	347	347	282
16	A2u	347	350	350	350
17	Eg	350	350	350	350	2.172e+39 18.4	2.987e+39 25.4	5.159e+39 43.8
18	Eg	350	390	390	439	2.172e+39 18.4	2.987e+39 25.4	5.159e+39 43.8

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥