- CELESTINE - SrSO₄

he 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. Unstable structure

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:	62		Pnma
Lattice parameters (Å):	8.3770	5.3500		6.8730
Angles (°):	90	90		90

Symmetry (theoretical):

Space group:	62		Pnma
Lattice parameters (Å):	8.1425	5.1443		6.6634
Angles (°):	90	90		90

Cell contents:

Number of atoms:	24
Number of atom types:	3
Chemical composition:	0

Atomic positions (theoretical):

Sr:	0.1824	0.2500	0.1569
S:	0.4357	0.7500	0.1866
O:	0.5968	0.7500	0.0920
O:	0.3009	0.7500	0.0402
O:	0.4195	0.9826	0.3161
Sr:	0.3176	0.7500	0.6569
S:	0.0643	0.2500	0.6866
O:	0.9032	0.2500	0.5920
O:	0.1991	0.2500	0.5402
O:	0.0805	0.0174	0.8161
Sr:	0.8176	0.7500	0.8431
S:	0.5643	0.2500	0.8134
O:	0.4032	0.2500	0.9080
O:	0.6991	0.2500	0.9598
O:	0.5805	0.4826	0.6839
Sr:	0.6824	0.2500	0.3431
S:	0.9357	0.7500	0.3134
O:	0.0968	0.7500	0.4080
O:	0.8009	0.7500	0.4598
O:	0.9195	0.5174	0.1839
O:	0.5805	0.0174	0.6839
O:	0.9195	0.9826	0.1839
O:	0.4195	0.5174	0.3161
O:	0.0805	0.4826	0.8161

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	B1u	-44	-44	-44	-44
2	B2u	-44	-44	0	-44
3	Ac	0	0	0	0
4	Ac	0	0	0	0
5	Ac	0	0	56	0
6	B1g	56	56	57	56
7	B2g	57	57	80	57
8	B2g	80	80	92	80
9	Ag	99	99	99	99	9.956e+38 0.5	4.118e+38 0.2	1.407e+39 0.7
10	B3u	99	103	99	99
11	Ag	103	109	103	103	8.259e+38 0.4	8.003e+37 0.0	9.060e+38 0.4
12	Au	109	115	109	109	4.151e+37 0.0	5.708e+37 0.0	9.858e+37 0.0
13	B1g	131	131	131	131	1.765e+39 0.8	2.427e+39 1.1	4.192e+39 2.0
14	B3g	138	138	138	145
15	B3u	145	151	145	151
16	B1u	151	152	151	157	2.353e+38 0.1	3.236e+38 0.2	5.589e+38 0.3
17	Ag	157	157	157	157	2.444e+37 0.0	1.826e+37 0.0	4.271e+37 0.0
18	B2g	163	163	163	163
19	B3g	164	164	164	165
20	Au	165	165	165	165	1.263e+38 0.1	1.737e+38 0.1	3.000e+38 0.1
21	B1u	169	169	169	169
22	B3u	180	181	180	180
23	B2u	181	181	181	181
24	B1g	181	184	196	181
25	Au	196	196	202	196
26	B1u	202	202	205	202	1.794e+37 0.0	2.467e+37 0.0	4.261e+37 0.0
27	Ag	205	205	212	205	2.032e+39 1.0	1.178e+37 0.0	2.044e+39 1.0
28	B2g	212	212	215	212
29	B3g	215	215	219	222
30	B1g	222	222	222	231	9.301e+37 0.0	1.279e+38 0.1	2.209e+38 0.1
31	Au	231	231	231	237	2.077e+38 0.1	2.856e+38 0.1	4.933e+38 0.2
32	Au	237	237	237	244	1.150e+37 0.0	1.582e+37 0.0	2.732e+37 0.0
33	B2u	244	244	251	246
34	B3g	251	251	254	254
35	B3u	254	254	254	254
36	Ag	254	296	255	270	1.742e+38 0.1	5.808e+37 0.0	2.323e+38 0.1
37	Au	443	443	443	443	2.307e+39 1.1	3.172e+39 1.5	5.480e+39 2.6
38	Ag	446	446	446	446	1.288e+40 6.0	9.428e+39 4.4	2.231e+40 10.5
39	B3g	452	452	452	452
40	B1g	460	460	460	460	1.547e+40 7.3	2.128e+40 10.0	3.675e+40 17.2
41	B1u	465	465	465	465	2.252e+38 0.1	3.097e+38 0.1	5.349e+38 0.3
42	B2u	465	465	465	465
43	B3u	471	471	471	471
44	B2g	483	483	483	483
45	B2g	579	579	579	579
46	B2u	585	585	597	585
47	B3g	597	597	602	602
48	B3u	602	602	604	605
49	B1u	605	605	605	606	8.965e+39 4.2	1.233e+40 5.8	2.129e+40 10.0
50	Ag	606	606	606	607	7.386e+39 3.5	4.947e+39 2.3	1.233e+40 5.8
51	B1g	607	607	607	616	1.159e+38 0.1	1.594e+38 0.1	2.753e+38 0.1
52	Au	618	618	618	618	1.155e+39 0.5	1.588e+39 0.7	2.743e+39 1.3
53	B3u	634	637	634	634
54	Ag	637	655	637	637	2.099e+39 1.0	1.573e+39 0.7	3.672e+39 1.7
55	B3g	655	656	655	656
56	Au	656	659	656	656	4.268e+39 2.0	5.868e+39 2.7	1.014e+40 4.7
57	B3u	990	991	990	990
58	Au	996	996	996	996	5.499e+37 0.0	7.562e+37 0.0	1.306e+38 0.1
59	B3g	997	997	997	999
60	Ag	1003	1003	1003	1003	2.132e+41 99.9	1.472e+38 0.1	2.134e+41 100.0
61	B2u	1074	1074	1074	1074
62	B2g	1074	1074	1104	1074
63	B1u	1104	1104	1105	1104	5.231e+39 2.5	7.192e+39 3.4	1.242e+40 5.8
64	B1g	1105	1105	1117	1105	1.126e+37 0.0	1.549e+37 0.0	2.675e+37 0.0
65	B3g	1117	1117	1118	1118
66	Ag	1118	1118	1143	1143	3.799e+39 1.8	1.652e+39 0.8	5.450e+39 2.6
67	B3u	1143	1143	1171	1171
68	Au	1171	1171	1173	1173	7.579e+39 3.6	1.042e+40 4.9	1.800e+40 8.4
69	Ag	1173	1173	1173	1193	7.790e+39 3.7	4.120e+39 1.9	1.191e+40 5.6
70	B3u	1193	1209	1193	1201
71	Au	1209	1260	1209	1209	6.907e+38 0.3	9.497e+38 0.4	1.640e+39 0.8
72	B3g	1260	1278	1260	1267

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥