- SIBIRSKITE - CaHBO₃

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:	14		P2_1/a
Lattice parameters (Å):	15.1920	5.6290		3.7067
Angles (°):	90.0	104.5		90.0

Symmetry (theoretical):

Space group:	14		P2_1/a
Lattice parameters (Å):	14.0081	5.1375		3.2813
Angles (°):	90.0	103.0		90.0

Cell contents:

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

Atomic positions (theoretical):

Ca:	0.1635	0.0072	0.2578
B:	0.1267	0.5037	0.8436
H:	0.0050	0.7248	0.5140
O:	0.2109	0.5127	0.1450
O:	0.0831	0.7369	0.6964
O:	0.0855	0.2730	0.6957
Ca:	0.3365	0.5072	0.7422
B:	0.3733	0.0037	0.1564
H:	0.4950	0.2248	0.4860
O:	0.2891	0.0127	0.8550
O:	0.4169	0.2369	0.3036
O:	0.4145	0.7730	0.3043
Ca:	0.8365	0.9928	0.7422
B:	0.8733	0.4963	0.1564
H:	0.9950	0.2752	0.4860
O:	0.7891	0.4873	0.8550
O:	0.9169	0.2631	0.3036
O:	0.9145	0.7270	0.3043
Ca:	0.6635	0.4928	0.2578
B:	0.6267	0.9963	0.8436
H:	0.5050	0.7752	0.5140
O:	0.7109	0.9873	0.1450
O:	0.5831	0.7631	0.6964
O:	0.5855	0.2270	0.6957

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.

Parameters of the Calculation

All the calculations have been done using the ABINIT software. This is a list of the most representative parameteres used during the Raman calculation.

Number of electronic bands:	26
k-points
grid:	1 4 6
number of shifts:	1
shifts:	0.5 0.5 0.5
Kinetic energy cut-off:	40 Ha [=1088.464 eV ]
eXchange-Correlation functional:	LDA pw90

Pseudopotentials:
Ca:	calcium, fhi98PP : Trouiller-Martins-type, LDA Ceperley/Alder Perdew/Wang (1992), l= 0 local
B:	boron, fhi98PP : Trouiller-Martins-type, LDA Ceperley/Alder Perdew/Wang (1992), l= 2 local
H:	hydrogen, fhi98PP : Trouiller-Martins-type, LDA Ceperley/Alder Perdew/Wang (1992), l= 2 local
O:	oxygen, fhi98PP : Trouiller-Martins-type, LDA Ceperley/Alder Perdew/Wang (1992), l= 2 local

Dielectric Properties

We define:

The Born effective charges, also called dynamical charges, are tensors that correspond to the energy derivative with respect to atomic displacements and electric fields or, equivalently, to the change in atomic force due to an electric field: The sum of the Born effective charges of all nuclei in one cell must vanish, element by element, along each of the three directions of the space.
The dielectric tensors are the energy derivative with respect to two electric fields. They also relate the induced polarization to the external electric field.

Born effective charges (Z):

Ca:	2.1275	-0.0043	-0.0073
	-0.0274	2.4027	-0.0028
	-0.0068	0.0058	2.3110
Eig. Value:	2.1263	2.4036	2.3112
B:	1.6102	0.0025	0.9094
	0.0143	2.2408	0.0454
	0.9271	0.0404	1.9449
Eig. Value:	0.8438	2.2380	2.7140
H:	1.8836	0.0346	0.9774
	0.0262	0.2772	0.0141
	0.9899	0.0261	0.9384
Eig. Value:	2.5029	0.2766	0.3197
O:	-1.8819	-0.0260	-0.5656
	-0.0420	-1.3862	-0.0421
	-0.6243	-0.0286	-2.0600
Eig. Value:	-1.3689	-1.3847	-2.5746
O:	-1.8854	0.2137	-0.6964
	0.1533	-1.7021	0.2352
	-0.6799	0.2310	-1.5400
Eig. Value:	-2.5236	-1.6084	-0.9955
O:	-1.8539	-0.2176	-0.6175
	-0.1519	-1.8324	-0.2598
	-0.6060	-0.2659	-1.5942
Eig. Value:	-2.4948	-1.6986	-1.0871
Ca:	2.1275	0.0043	-0.0073
	0.0274	2.4027	0.0028
	-0.0068	-0.0058	2.3110
Eig. Value:	2.1263	2.4036	2.3112
B:	1.6102	-0.0025	0.9094
	-0.0143	2.2408	-0.0454
	0.9271	-0.0404	1.9449
Eig. Value:	0.8438	2.2380	2.7140
H:	1.8836	-0.0346	0.9774
	-0.0262	0.2772	-0.0141
	0.9899	-0.0261	0.9384
Eig. Value:	2.5029	0.2766	0.3197
O:	-1.8819	0.0260	-0.5656
	0.0420	-1.3862	0.0421
	-0.6243	0.0286	-2.0600
Eig. Value:	-1.3689	-1.3847	-2.5746
O:	-1.8854	-0.2137	-0.6964
	-0.1533	-1.7021	-0.2352
	-0.6799	-0.2310	-1.5400
Eig. Value:	-2.5236	-1.6084	-0.9955
O:	-1.8539	0.2176	-0.6175
	0.1519	-1.8324	0.2598
	-0.6060	0.2659	-1.5942
Eig. Value:	-2.4948	-1.6986	-1.0871
Ca:	2.1275	-0.0043	-0.0073
	-0.0274	2.4027	-0.0028
	-0.0068	0.0058	2.3110
Eig. Value:	2.1263	2.4036	2.3112
B:	1.6102	0.0025	0.9094
	0.0143	2.2408	0.0454
	0.9271	0.0404	1.9449
Eig. Value:	0.8438	2.2380	2.7140
H:	1.8836	0.0346	0.9774
	0.0262	0.2772	0.0141
	0.9899	0.0261	0.9384
Eig. Value:	2.5029	0.2766	0.3197
O:	-1.8819	-0.0260	-0.5656
	-0.0420	-1.3862	-0.0421
	-0.6243	-0.0286	-2.0600
Eig. Value:	-1.3689	-1.3847	-2.5746
O:	-1.8854	0.2137	-0.6964
	0.1533	-1.7021	0.2352
	-0.6799	0.2310	-1.5400
Eig. Value:	-2.5236	-1.6084	-0.9955
O:	-1.8539	-0.2176	-0.6175
	-0.1519	-1.8324	-0.2598
	-0.6060	-0.2659	-1.5942
Eig. Value:	-2.4948	-1.6986	-1.0871
Ca:	2.1275	0.0043	-0.0073
	0.0274	2.4027	0.0028
	-0.0068	-0.0058	2.3110
Eig. Value:	2.1263	2.4036	2.3112
B:	1.6102	-0.0025	0.9094
	-0.0143	2.2408	-0.0454
	0.9271	-0.0404	1.9449
Eig. Value:	0.8438	2.2380	2.7140
H:	1.8836	-0.0346	0.9774
	-0.0262	0.2772	-0.0141
	0.9899	-0.0261	0.9384
Eig. Value:	2.5029	0.2766	0.3197
O:	-1.8819	0.0260	-0.5656
	0.0420	-1.3862	0.0421
	-0.6243	0.0286	-2.0600
Eig. Value:	-1.3689	-1.3847	-2.5746
O:	-1.8854	-0.2137	-0.6964
	-0.1533	-1.7021	-0.2352
	-0.6799	-0.2310	-1.5400
Eig. Value:	-2.5236	-1.6084	-0.9955
O:	-1.8539	0.2176	-0.6175
	0.1519	-1.8324	0.2598
	-0.6060	0.2659	-1.5942
Eig. Value:	-2.4948	-1.6986	-1.0871

Atom type

Dielectric tensors:

	X	Y	Z
Ɛ_∞:	2.8248	0.0000	0.2717
	0.0000	2.7824	0.0000
	0.2717	0.0000	2.8805
Eig. Value:	2.5796	2.7824	3.1258
Refractive index (N):	1.6807	-0.0000	0.5212
	-0.0000	1.6680	-0.0000
	0.5212	-0.0000	1.6972
Eig. Value:	1.6061	1.6680	1.7680
Ɛ₀:	0.0000	0.0000	0.0000
	0.0000	0.0000	0.0000
	0.0000	0.0000	0.0000
Eig. Value:	0.0000	0.0000	0.0000

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	41	41	41	41	8.173e+38 0.8	5.648e+38 0.6	1.382e+39 1.4
5	Bg	55	55	55	55
6	Ag	109	109	109	109	7.255e+37 0.1	3.653e+37 0.0	1.091e+38 0.1
7	Bu	120	120	120	120
8	Bg	125	125	125	125	1.622e+38 0.2	2.050e+38 0.2	3.672e+38 0.4
9	Au	135	135	135	135
10	Ag	158	158	158	158	1.352e+39 1.3	1.076e+39 1.1	2.428e+39 2.4
11	Bg	163	163	163	163	3.539e+39 3.5	5.971e+39 5.9	9.511e+39 9.4
12	Bg	176	176	176	176	2.628e+39 2.6	4.427e+39 4.4	7.055e+39 7.0
13	Au	198	198	205	198
14	Ag	205	205	219	205	1.460e+39 1.4	7.179e+38 0.7	2.178e+39 2.2
15	Au	221	221	226	221
16	Ag	226	226	229	226	4.080e+39 4.0	3.468e+39 3.4	7.548e+39 7.5
17	Bg	229	229	231	229	4.766e+39 4.7	7.768e+39 7.7	1.253e+40 12.4
18	Bu	232	234	232	233
19	Au	235	235	236	235
20	Bu	236	243	242	236
21	Au	243	246	259	243
22	Bu	259	265	265	260
23	Ag	265	268	268	265	2.387e+39 2.4	9.146e+38 0.9	3.301e+39 3.3
24	Au	268	278	284	268
25	Ag	284	284	291	284	1.881e+40 18.6	6.737e+39 6.7	2.555e+40 25.3
26	Bg	291	291	293	291	4.848e+38 0.5	6.917e+38 0.7	1.176e+39 1.2
27	Bu	293	309	309	294
28	Bg	309	316	315	309	6.342e+38 0.6	6.744e+38 0.7	1.309e+39 1.3
29	Au	325	325	325	325
30	Ag	331	331	331	331	5.633e+39 5.6	1.181e+39 1.2	6.814e+39 6.7
31	Bu	332	338	332	338
32	Bg	338	374	338	374	4.981e+39 4.9	5.322e+39 5.3	1.030e+40 10.2
33	Ag	374	386	374	389	1.862e+39 1.8	4.308e+38 0.4	2.293e+39 2.3
34	Au	395	395	409	395
35	Bg	409	409	419	409	2.568e+39 2.5	2.730e+39 2.7	5.299e+39 5.2
36	Bu	419	422	419	422
37	Ag	500	500	500	500	1.662e+40 16.5	1.182e+40 11.7	2.844e+40 28.2
38	Bg	513	513	513	513	7.469e+38 0.7	8.240e+38 0.8	1.571e+39 1.6
39	Ag	625	625	625	625	1.566e+39 1.6	1.440e+39 1.4	3.006e+39 3.0
40	Ag	625	625	625	625	1.833e+39 1.8	1.686e+39 1.7	3.519e+39 3.5
41	Bu	630	631	630	633
42	Bg	633	633	633	633	2.176e+36 0.0	3.651e+36 0.0	5.827e+36 0.0
43	Bu	680	684	680	680
44	Bu	684	686	684	686
45	Au	686	686	686	686
46	Bg	686	687	686	687	1.008e+38 0.1	1.567e+38 0.2	2.576e+38 0.3
47	Ag	687	707	687	707	1.142e+40 11.3	1.701e+39 1.7	1.312e+40 13.0
48	Au	707	713	714	720
49	Ag	900	900	900	900	8.741e+40 86.6	1.358e+40 13.4	1.010e+41 100.0
50	Bg	902	902	902	902	1.857e+38 0.2	2.681e+38 0.3	4.538e+38 0.4
51	Bu	911	920	911	918
52	Au	920	921	920	920
53	Ag	1034	1034	1034	1034	1.605e+40 15.9	1.753e+40 17.4	3.357e+40 33.2
54	Bg	1037	1037	1037	1037	4.475e+38 0.4	4.922e+38 0.5	9.397e+38 0.9
55	Ag	1205	1205	1205	1205	1.232e+38 0.1	9.205e+37 0.1	2.153e+38 0.2
56	Bg	1206	1206	1206	1206	2.887e+38 0.3	3.071e+38 0.3	5.958e+38 0.6
57	Bu	1208	1231	1208	1233
58	Au	1233	1233	1233	1243
59	Bu	1247	1314	1247	1314
60	Au	1314	1317	1319	1318
61	Bu	1319	1339	1339	1339
62	Ag	1339	1353	1340	1353	1.220e+39 1.2	1.008e+39 1.0	2.228e+39 2.2
63	Au	1353	1367	1357	1374
64	Bg	1378	1378	1378	1378	2.408e+37 0.0	4.062e+37 0.0	6.470e+37 0.1
65	Bu	1431	1436	1431	1436
66	Au	1436	1438	1503	1438
67	Bg	1503	1503	1504	1503	1.084e+39 1.1	1.520e+39 1.5	2.604e+39 2.6
68	Ag	1504	1504	1505	1504	7.843e+39 7.8	3.960e+39 3.9	1.180e+40 11.7
69	Ag	1557	1557	1557	1557	1.766e+40 17.5	1.398e+40 13.8	3.164e+40 31.3
70	Bg	1562	1562	1562	1562	4.594e+38 0.5	6.910e+38 0.7	1.150e+39 1.1
71	Bu	1733	2047	1733	1834
72	Au	2116	2116	2116	2116

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥

I Total

You can define the size of the supercell for the visualization of the vibration.

Normalized

Raw

Options for intensity.

Single Crystal Raman spectra

Single crystal Raman spectrum

The Raman measurements performed on single crystals employ polarized lasers and allow for the selection of specific elements of the individual Raman tensors of the Raman-active modes.

By convention, in the following we assume a measurement as X(XZ)Z, i.e. incident laser polarized along the X axis, emergent light polarized along the Z axis. If the crystal is aligned with the xyz reference frame, we sample the α_xz element. As you rotate the crystal you can sample other entries of the Raman tensor or various linear combineations.