- ARAGONITE - CaCO₃

Theoretical atomic positions. Lattice parameters fixed as in RRUFF entry #R060195

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):	4.9608	7.9688		5.7411
Angles (°):	90.0	90.0		90.0

Symmetry (theoretical):

Space group:	62		Pnma
Lattice parameters (Å):	4.9608	7.9688		5.7411
Angles (°):	90.0	90.0		90.0

Cell contents:

Number of atoms:	20
Number of atom types:	3
Chemical composition:	0

Atomic positions (theoretical):

Ca:	0.2500	0.5494	0.2505
C:	0.2500	0.7640	0.8841
O:	0.2500	0.9247	0.8686
O:	0.4751	0.6870	0.9006
Ca:	0.7500	0.9506	0.7505
C:	0.7500	0.7360	0.3841
O:	0.7500	0.5753	0.3686
O:	0.5249	0.8130	0.4006
Ca:	0.7500	0.4506	0.7495
C:	0.7500	0.2360	0.1159
O:	0.7500	0.0753	0.1314
O:	0.9751	0.3130	0.0994
Ca:	0.2500	0.0494	0.2495
C:	0.2500	0.2640	0.6159
O:	0.2500	0.4247	0.6314
O:	0.0249	0.1870	0.5994
O:	0.5249	0.3130	0.0994
O:	0.4751	0.1870	0.5994
O:	0.0249	0.6870	0.9006
O:	0.9751	0.8130	0.4006

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	A1u	25	25	25	25
5	A2g	43	43	43	43	1.630e+39 1.6	2.241e+39 2.2	3.871e+39 3.7
6	A1u	94	94	94	94
7	A1g	110	110	110	110	7.445e+38 0.7	3.809e+38 0.4	1.125e+39 1.1
8	B1u	115	115	122	115
9	B2u	124	126	124	124
10	B1g	126	127	126	126	4.215e+38 0.4	5.795e+38 0.6	1.001e+39 1.0
11	A2g	134	134	134	134	1.043e+39 1.0	1.434e+39 1.4	2.477e+39 2.4
12	A1u	149	149	149	149
13	B1g	155	155	155	155	4.072e+39 3.9	5.599e+39 5.4	9.671e+39 9.4
14	A2u	167	167	167	172
15	A1g	172	172	172	172	4.550e+39 4.4	1.671e+39 1.6	6.221e+39 6.0
16	A1u	172	172	172	173
17	A2g	173	173	173	175	4.981e+39 4.8	6.849e+39 6.6	1.183e+40 11.5
18	B2g	175	175	175	178	8.266e+36 0.0	1.137e+37 0.0	1.963e+37 0.0
19	A1g	178	178	178	181	1.737e+39 1.7	5.559e+38 0.5	2.293e+39 2.2
20	B1g	181	181	181	188	5.157e+39 5.0	7.090e+39 6.9	1.225e+40 11.9
21	B2u	191	198	191	191
22	B1u	198	220	220	198
23	A2u	220	223	223	223
24	A2g	223	227	227	227	1.541e+37 0.0	2.118e+37 0.0	3.659e+37 0.0
25	B2g	227	228	228	228	1.801e+39 1.7	2.477e+39 2.4	4.278e+39 4.1
26	A1g	228	239	228	239	3.818e+39 3.7	1.401e+39 1.4	5.219e+39 5.1
27	B2g	239	241	239	241	7.248e+39 7.0	9.966e+39 9.7	1.721e+40 16.7
28	B2g	241	244	241	243	1.023e+39 1.0	1.406e+39 1.4	2.429e+39 2.4
29	A2u	244	249	244	249
30	B1g	249	251	249	251	1.053e+40 10.2	1.447e+40 14.0	2.500e+40 24.2
31	B2u	251	255	251	255
32	B1u	255	278	266	278
33	B1u	278	283	283	279
34	A1g	283	292	292	283	2.059e+39 2.0	9.415e+38 0.9	3.001e+39 2.9
35	B2g	292	315	329	292	6.804e+39 6.6	9.355e+39 9.1	1.616e+40 15.7
36	A2u	329	329	352	387
37	B2g	674	674	674	674	8.935e+37 0.1	1.229e+38 0.1	2.122e+38 0.2
38	A2u	677	677	677	677
39	A1g	682	682	682	682	5.596e+39 5.4	3.875e+39 3.8	9.471e+39 9.2
40	B1u	688	688	690	688
41	B2u	696	698	696	696
42	A1u	699	699	699	699
43	A2g	701	701	701	701	2.065e+39 2.0	2.840e+39 2.8	4.905e+39 4.8
44	B1g	702	702	702	702	4.406e+38 0.4	6.059e+38 0.6	1.047e+39 1.0
45	A1g	855	855	855	855	1.224e+39 1.2	2.817e+38 0.3	1.505e+39 1.5
46	A2u	856	856	856	861
47	B1u	861	861	861	862
48	B2g	862	862	862	869	1.714e+38 0.2	2.357e+38 0.2	4.071e+38 0.4
49	B1u	1083	1083	1083	1083
50	B2g	1084	1084	1084	1084	1.162e+37 0.0	1.598e+37 0.0	2.761e+37 0.0
51	A1g	1084	1084	1084	1084	1.003e+41 97.1	2.956e+39 2.9	1.032e+41 100.0
52	A2u	1085	1085	1085	1085
53	B2u	1402	1421	1402	1402
54	B1g	1421	1423	1421	1421	3.376e+39 3.3	4.642e+39 4.5	8.018e+39 7.8
55	B1u	1423	1430	1430	1423
56	A1g	1430	1454	1454	1430	6.583e+38 0.6	6.264e+36 0.0	6.645e+38 0.6
57	A2u	1454	1458	1458	1454
58	A1u	1458	1476	1476	1458
59	A2g	1476	1538	1538	1476	2.191e+39 2.1	3.013e+39 2.9	5.204e+39 5.0
60	B2g	1538	1542	1547	1538	4.224e+38 0.4	5.808e+38 0.6	1.003e+39 1.0

No.

Char.

ω TO

ω LOx

ω LOy

ω LOz

I ∥

I ⊥