- JOHACHIDOLITE - CaAlB₃O₇

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:	67		Cmma
Lattice parameters (Å):	7.9670	11.7230		4.3718
Angles (°):	90	90		90

Symmetry (theoretical):

Space group:	67		Cmma
Lattice parameters (Å):	7.7518	7.7518		4.3895
Angles (°):	90	90		66.80

Cell contents:

Number of atoms:	24
Number of atom types:	4
Chemical composition:	0

Atomic positions (theoretical):

Ca:	0.5000	0.0000	0.0000
Al:	0.0000	0.0000	0.0000
Al:	0.2500	0.7500	0.5000
B:	0.1248	0.1248	0.4196
B:	0.2500	0.2500	0.3938
O:	0.1168	0.1168	0.7447
O:	0.2076	0.9375	0.2596
Ca:	0.0000	0.5000	0.0000
Al:	0.5000	0.5000	0.0000
B:	0.3752	0.3752	0.4196
O:	0.3832	0.3832	0.7447
O:	0.2924	0.5625	0.2596
B:	0.6248	0.6248	0.5804
B:	0.7500	0.7500	0.6062
O:	0.6168	0.6168	0.2553
O:	0.4375	0.7076	0.7404
B:	0.8752	0.8752	0.5804
O:	0.8832	0.8832	0.2553
O:	0.0625	0.7924	0.7404
Al:	0.7500	0.2500	0.5000
O:	0.7924	0.0625	0.7404
O:	0.7076	0.4375	0.7404
O:	0.5625	0.2924	0.2596
O:	0.9375	0.2076	0.2596

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	Au	-98	-98	-98	-98
2	B3u	-91	-87	-91	-91
3	B2g	-78	-78	-78	-78
4	B2u	-69	-69	-56	-69
5	B1u	-24	-24	-24	-1
6	B3u	-1	-1	0	0
7	B2u	0	0	0	0
8	B1u	0	0	1	20
9	B2u	52	52	84	52	6.138e+53 0.0	8.449e+53 0.0	1.459e+54 0.1
10	B3g	118	118	118	118
11	B3u	120	121	120	120	1.006e+56 5.9	1.384e+56 8.1	2.390e+56 14.0
12	B1u	143	143	143	152	2.990e+53 0.0	4.123e+53 0.0	7.113e+53 0.0
13	B1g	168	168	168	168	8.213e+55 4.8	1.165e+56 6.8	1.987e+56 11.6
14	Au	198	198	198	198	1.081e+55 0.6	1.489e+55 0.9	2.570e+55 1.5
15	B3g	203	203	203	203
16	B1u	210	210	210	212	9.710e+54 0.6	1.333e+55 0.8	2.304e+55 1.4
17	B2g	229	229	229	229	1.164e+54 0.1	1.691e+54 0.1	2.855e+54 0.2
18	B3u	235	237	235	235	1.112e+54 0.1	1.506e+54 0.1	2.617e+54 0.2
19	B1g	260	260	260	260	7.156e+56 42.0	9.899e+56 58.0	1.705e+57 100.0
20	B2u	270	270	278	270	8.731e+52 0.0	1.207e+53 0.0	2.080e+53 0.0
21	B2g	281	281	281	281	1.785e+52 0.0	2.825e+52 0.0	4.610e+52 0.0
22	Ag	289	289	289	289	7.718e+53 0.0	1.360e+53 0.0	9.078e+53 0.1
23	B3u	311	312	311	311	2.533e+53 0.0	3.473e+53 0.0	6.006e+53 0.0
24	Ag	313	313	313	313	4.538e+53 0.0	8.958e+52 0.0	5.434e+53 0.0
25	B2g	323	323	323	323	1.239e+56 7.3	1.704e+56 10.0	2.943e+56 17.3
26	B3g	327	327	327	327	1.528e+52 0.0	2.081e+52 0.0	3.609e+52 0.0
27	B1g	330	330	330	330	3.227e+56 18.9	4.437e+56 26.0	7.664e+56 44.9
28	Au	340	340	340	340	1.939e+54 0.1	2.668e+54 0.2	4.606e+54 0.3
29	B1u	353	353	353	353	4.138e+55 2.4	5.685e+55 3.3	9.823e+55 5.8
30	B2u	382	382	391	382
31	B3u	414	414	414	414	9.100e+51 0.0	1.231e+52 0.0	2.141e+52 0.0
32	B3u	425	425	425	425	1.233e+52 0.0	1.716e+52 0.0	2.949e+52 0.0
33	Au	429	429	429	429
34	B1u	436	436	436	442	1.381e+53 0.0	1.911e+53 0.0	3.293e+53 0.0
35	B1u	457	457	457	471	9.957e+51 0.0	1.441e+52 0.0	2.437e+52 0.0
36	B2u	476	476	477	476
37	Ag	498	498	498	498	3.805e+54 0.2	5.230e+54 0.3	9.035e+54 0.5
38	B1g	498	498	498	498	2.047e+56 12.0	2.587e+56 15.2	4.634e+56 27.2
39	Au	499	499	499	499	1.938e+54 0.1	2.180e+54 0.1	4.119e+54 0.2
40	B3g	501	501	501	501	9.471e+52 0.0	1.296e+53 0.0	2.243e+53 0.0
41	Ag	512	512	512	512	3.200e+54 0.2	1.786e+54 0.1	4.986e+54 0.3
42	B1u	520	520	520	523	1.831e+54 0.1	2.427e+54 0.1	4.258e+54 0.2
43	B3u	536	536	536	536	1.877e+52 0.0	2.421e+52 0.0	4.298e+52 0.0
44	B2g	539	539	539	539
45	B1u	561	561	561	574	8.559e+52 0.0	1.117e+53 0.0	1.973e+53 0.0
46	B2u	585	585	586	585
47	Au	617	617	617	617
48	B2u	631	631	640	631
49	B3g	644	644	644	644
50	B1u	686	686	686	686
51	B2u	690	690	694	690
52	B1g	697	697	697	697	2.538e+52 0.0	3.489e+52 0.0	6.027e+52 0.0
53	Ag	702	702	702	702	1.418e+53 0.0	5.444e+52 0.0	1.962e+53 0.0
54	B3g	721	721	721	721
55	B2g	737	737	737	737
56	B3u	753	753	753	753
57	B2g	804	804	804	804	1.269e+52 0.0	1.662e+52 0.0	2.931e+52 0.0
58	B3u	810	813	810	810
59	Ag	820	820	820	820	4.652e+53 0.0	6.192e+53 0.0	1.084e+54 0.1
60	B1g	821	821	821	821	7.454e+51 0.0	1.025e+52 0.0	1.770e+52 0.0
61	B2u	868	868	868	868	1.603e+53 0.0	2.204e+53 0.0	3.806e+53 0.0
62	B1u	868	868	873	870	4.161e+52 0.0	5.741e+52 0.0	9.902e+52 0.0
63	B3g	881	881	881	881
64	Au	934	934	934	934	1.878e+52 0.0	2.581e+52 0.0	4.459e+52 0.0
65	B1u	956	956	956	957
66	Ag	990	990	990	990	9.196e+53 0.1	9.299e+53 0.1	1.850e+54 0.1
67	B3g	1001	1001	1001	1001
68	B2u	1008	1008	1008	1008
69	B1u	1032	1032	1032	1051	1.916e+52 0.0	2.654e+52 0.0	4.570e+52 0.0
70	Ag	1065	1065	1065	1065	1.028e+55 0.6	6.208e+54 0.4	1.649e+55 1.0
71	B2u	1254	1254	1256	1254	5.599e+54 0.3	7.699e+54 0.5	1.330e+55 0.8
72	B3g	1256	1256	1256	1256

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥