- COLQUIRIITE - LiCaAlF₆

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:	163		P-31c
Lattice parameters (Å):	4.9960	4.9960		9.6360
Angles (°):	90.0	90.0		120.0

Symmetry (theoretical):

Space group:	163		P-31c
Lattice parameters (Å):	4.8959	4.8959		9.6254
Angles (°):	90.0	90.0		120.0

Cell contents:

Number of atoms:	18
Number of atom types:	4
Chemical composition:	0

Atomic positions (theoretical):

Ca:	0.0000	0.0000	0.0000
Li:	0.3333	0.6667	0.2500
Al:	0.6667	0.3333	0.2500
F:	0.3784	0.0255	0.1447
F:	0.6471	0.6216	0.1447
Ca:	0.0000	0.0000	0.5000
Li:	0.6667	0.3333	0.7500
Al:	0.3333	0.6667	0.7500
F:	0.0255	0.3784	0.6447
F:	0.9745	0.3529	0.1447
F:	0.3529	0.9745	0.6447
F:	0.6216	0.6471	0.6447
F:	0.6216	0.9745	0.8553
F:	0.3529	0.3784	0.8553
F:	0.9745	0.6216	0.3553
F:	0.0255	0.6471	0.8553
F:	0.6471	0.0255	0.3553
F:	0.3784	0.3529	0.3553

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	Eg	102	102	102	102	9.231e+36 0.1	9.931e+36 0.1	1.916e+37 0.2
5	Eg	102	102	102	102	9.232e+36 0.1	1.064e+37 0.1	1.987e+37 0.2
6	Eu	120	120	120	120
7	Eu	120	123	123	120
8	A2g	123	125	125	123
9	A2u	125	126	126	156
10	Eg	163	163	163	163	1.732e+38 1.7	2.173e+38 2.1	3.905e+38 3.8
11	Eg	163	163	163	163	1.732e+38 1.7	2.451e+38 2.4	4.182e+38 4.0
12	Eu	191	191	191	191
13	Eu	191	206	206	191
14	Eu	207	207	207	207
15	Eu	207	208	208	207
16	A1u	236	236	236	236
17	Eg	255	255	255	255
18	Eg	255	255	255	255
19	A2g	257	257	257	257
20	A1g	269	269	269	269	1.637e+39 15.7	3.318e+36 0.0	1.640e+39 15.8
21	A1u	283	283	283	283
22	A2u	285	285	285	285
23	Eu	297	297	297	297
24	Eu	297	300	300	297
25	A2g	300	302	302	300
26	Eu	320	320	320	320
27	Eu	320	326	326	320
28	Eg	326	326	326	326	4.308e+38 4.1	7.115e+38 6.8	1.142e+39 11.0
29	Eg	326	334	334	326	4.308e+38 4.1	5.206e+38 5.0	9.514e+38 9.1
30	A2u	348	348	348	383
31	A1g	383	383	383	392	1.304e+39 12.5	7.309e+37 0.7	1.378e+39 13.2
32	Eg	392	392	392	392	1.180e+38 1.1	1.430e+38 1.4	2.610e+38 2.5
33	Eg	392	392	392	401	1.180e+38 1.1	9.868e+37 0.9	2.167e+38 2.1
34	Eu	401	401	401	401
35	Eu	401	413	413	401
36	A1u	413	417	417	413
37	A2g	418	418	418	418
38	A2u	428	428	428	428
39	Eg	435	435	435	435	6.148e+38 5.9	5.917e+38 5.7	1.206e+39 11.6
40	Eg	435	435	435	435	6.148e+38 5.9	9.780e+38 9.4	1.593e+39 15.3
41	Eu	441	441	441	441
42	Eu	441	457	457	441
43	Eg	457	457	457	457	1.064e+38 1.0	9.228e+37 0.9	1.987e+38 1.9
44	Eg	457	466	466	457	1.065e+38 1.0	1.518e+38 1.5	2.583e+38 2.5
45	Eu	473	473	473	473
46	Eu	473	505	505	473
47	A1g	570	570	570	570	1.040e+40 100.0	3.459e+36 0.0	1.041e+40 100.0
48	Eu	585	585	585	585
49	Eu	585	586	586	585
50	Eg	586	586	586	586	4.720e+38 4.5	5.532e+38 5.3	1.025e+39 9.9
51	Eg	586	594	594	586	4.720e+38 4.5	7.889e+38 7.6	1.261e+39 12.1
52	A1u	594	594	594	594
53	A2u	594	693	693	709
54	A2g	709	709	709	717

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

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