Characters of representations for molecular motions
Motion |
E |
C2.(z) |
C2.(y) |
C2.(x) |
i |
σ.(xy) |
σ.(xy) |
σ.(xy) |
Cartesian 3N |
24 |
0 |
-2 |
-2 |
0 |
4 |
6 |
2 |
Translation (x,y,z) |
3 |
-1 |
-1 |
-1 |
-3 |
1 |
1 |
1 |
Rotation (Rx,Ry,Rz) |
3 |
-1 |
-1 |
-1 |
3 |
-1 |
-1 |
-1 |
Vibration |
18 |
2 |
0 |
0 |
0 |
4 |
6 |
2 |
Decomposition to irreducible representations
Motion |
A1g |
B1g |
B2g |
B3g |
A1u |
B1u |
B2u |
B3u |
Total |
Cartesian 3N |
4 |
3 |
3 |
2 |
1 |
4 |
3 |
4 |
24 |
Translation (x,y,z) |
0 |
0 |
0 |
0 |
0 |
1 |
1 |
1 |
3 |
Rotation (Rx,Ry,Rz) |
0 |
1 |
1 |
1 |
0 |
0 |
0 |
0 |
3 |
Vibration |
4 |
2 |
2 |
1 |
1 |
3 |
2 |
3 |
18 |
Molecular parameter
Number of Atoms (N) |
8
|
Number of internal coordinates |
18
|
Number of independant internal coordinates |
4
|
Number of vibrational modes |
18
|
Force field analysis
Allowed / forbidden vibronational transitions
Operator |
A1g |
B1g |
B2g |
B3g |
A1u |
B1u |
B2u |
B3u |
Total |
Linear (IR) |
4 |
2 |
2 |
1 |
1 |
3 |
2 |
3 |
8 / 10 |
Quadratic (Raman) |
4 |
2 |
2 |
1 |
1 |
3 |
2 |
3 |
9 / 9 |
IR + Raman |
- - - - |
- - - - |
- - - - |
- - - - |
1 |
- - - - |
- - - - |
- - - - |
0* / 1 |
* Parity Mutual Exclusion Principle
Characters of force fields
(Symmetric powers of vibration representation)
Force field |
E |
C2.(z) |
C2.(y) |
C2.(x) |
i |
σ.(xy) |
σ.(xy) |
σ.(xy) |
linear |
18 |
2 |
0 |
0 |
0 |
4 |
6 |
2 |
quadratic |
171 |
11 |
9 |
9 |
9 |
17 |
27 |
11 |
cubic |
1.140 |
20 |
0 |
0 |
0 |
48 |
92 |
20 |
quartic |
5.985 |
65 |
45 |
45 |
45 |
133 |
273 |
65 |
quintic |
26.334 |
110 |
0 |
0 |
0 |
308 |
714 |
110 |
sextic |
100.947 |
275 |
165 |
165 |
165 |
693 |
1.715 |
275 |
Decomposition to irreducible representations
Column with number of nonvanshing force constants highlighted
Force field |
A1g |
B1g |
B2g |
B3g |
A1u |
B1u |
B2u |
B3u |
linear |
4 |
2 |
2 |
1 |
1 |
3 |
2 |
3 |
quadratic |
33 |
19 |
21 |
17 |
17 |
22 |
19 |
23 |
cubic |
165 |
137 |
143 |
125 |
125 |
153 |
137 |
155 |
quartic |
832 |
725 |
755 |
703 |
703 |
765 |
725 |
777 |
quintic |
3.447 |
3.241 |
3.315 |
3.164 |
3.164 |
3.370 |
3.241 |
3.392 |
sextic |
13.050 |
12.470 |
12.698 |
12.338 |
12.338 |
12.753 |
12.470 |
12.830 |
Further Reading
- J.K.G. Watson, J. Mol. Spec. 41 229 (1972)
The Numbers of Structural Parameters and Potential Constants of Molecules
- X.F. Zhou, P. Pulay. J. Comp. Chem. 10 No. 7, 935-938 (1989)
Characters for Symmetric and Antisymmetric Higher Powers of Representations:
Application to the Number of Anharmonic Force Constants in Symmetrical Molecules
- F. Varga, L. Nemes, J.K.G. Watson. J. Phys. B: At. Mol. Opt. Phys. 10 No. 7, 5043-5048 (1996)
The number of anharmonic potential constants of the fullerenes C60 and C70
Contributions to nonvanishing force field constants
pos(X) : Position of irreducible representation (irrep) X in character table of D
2h
Subtotal: <Number of nonvanishing force constants in subsection> / <number of nonzero irrep combinations in subsection> / <number of irrep combinations in subsection>
Total: <Number of nonvanishing force constants in force field> / <number of nonzero irrep combinations in force field> / <number of irrep combinations in force field>
Contributions to nonvanishing quadratic force field constants
Irrep combinations (i,i) with indices: pos(A1g) ≤ i ≤ pos(B3u) |
..10. |
A1gA1g. | ..3. |
B1gB1g. | ..3. |
B2gB2g. | ..1. |
B3gB3g. | ..1. |
A1uA1u. | ..6. |
B1uB1u. | ..3. |
B2uB2u. | ..6. |
B3uB3u. | | |
| |
Subtotal: 33 / 8 / 8 |
Irrep combinations (i,j) with indices: pos(A1g) ≤ i ≤ j ≤ pos(B3u) |
Subtotal: 0 / 0 / 28 |
Total: 33 / 8 / 36 |
Contributions to nonvanishing cubic force field constants
Irrep combinations (i,i,i) with indices: pos(A1g) ≤ i ≤ pos(B3u) |
..20. |
A1gA1gA1g. | | |
| |
| |
| |
| |
| |
| |
| |
| |
Subtotal: 20 / 1 / 8 |
Irrep combinations (i,i,j) (i,j,j) with indices: pos(A1g) ≤ i ≤ j ≤ pos(B3u) |
..12. |
A1gB1gB1g. | ..12. |
A1gB2gB2g. | ..4. |
A1gB3gB3g. | ..4. |
A1gA1uA1u. | ..24. |
A1gB1uB1u. | ..12. |
A1gB2uB2u. | ..24. |
A1gB3uB3u. | | |
| |
| |
Subtotal: 92 / 7 / 56 |
Irrep combinations (i,j,k) with indices: pos(A1g) ≤ i ≤ j ≤ k ≤ pos(B3u) |
..4. |
B1gB2gB3g. | ..6. |
B1gA1uB1u. | ..12. |
B1gB2uB3u. | ..4. |
B2gA1uB2u. | ..18. |
B2gB1uB3u. | ..3. |
B3gA1uB3u. | ..6. |
B3gB1uB2u. | | |
| |
| |
Subtotal: 53 / 7 / 56 |
Total: 165 / 15 / 120 |
Contributions to nonvanishing quartic force field constants
Irrep combinations (i,i,i,i) with indices: pos(A1g) ≤ i ≤ pos(B3u) |
..35. |
A1gA1gA1gA1g. | ..5. |
B1gB1gB1gB1g. | ..5. |
B2gB2gB2gB2g. | ..1. |
B3gB3gB3gB3g. | ..1. |
A1uA1uA1uA1u. | ..15. |
B1uB1uB1uB1u. | ..5. |
B2uB2uB2uB2u. | ..15. |
B3uB3uB3uB3u. | | |
| |
Subtotal: 82 / 8 / 8 |
Irrep combinations (i,i,i,j) (i,j,j,j) with indices: pos(A1g) ≤ i ≤ j ≤ pos(B3u) |
Subtotal: 0 / 0 / 56 |
Irrep combinations (i,i,j,j) with indices: pos(A1g) ≤ i ≤ j ≤ pos(B3u) |
..30. |
A1gA1gB1gB1g. | ..30. |
A1gA1gB2gB2g. | ..10. |
A1gA1gB3gB3g. | ..10. |
A1gA1gA1uA1u. | ..60. |
A1gA1gB1uB1u. | ..30. |
A1gA1gB2uB2u. | ..60. |
A1gA1gB3uB3u. | ..9. |
B1gB1gB2gB2g. | ..3. |
B1gB1gB3gB3g. | ..3. |
B1gB1gA1uA1u. |
..18. |
B1gB1gB1uB1u. | ..9. |
B1gB1gB2uB2u. | ..18. |
B1gB1gB3uB3u. | ..3. |
B2gB2gB3gB3g. | ..3. |
B2gB2gA1uA1u. | ..18. |
B2gB2gB1uB1u. | ..9. |
B2gB2gB2uB2u. | ..18. |
B2gB2gB3uB3u. | ..1. |
B3gB3gA1uA1u. | ..6. |
B3gB3gB1uB1u. |
..3. |
B3gB3gB2uB2u. | ..6. |
B3gB3gB3uB3u. | ..6. |
A1uA1uB1uB1u. | ..3. |
A1uA1uB2uB2u. | ..6. |
A1uA1uB3uB3u. | ..18. |
B1uB1uB2uB2u. | ..36. |
B1uB1uB3uB3u. | ..18. |
B2uB2uB3uB3u. | | |
| |
Subtotal: 444 / 28 / 28 |
Irrep combinations (i,i,j,k) (i,j,j,k) (i,j,k,k) with indices: pos(A1g) ≤ i ≤ j ≤ k ≤ pos(B3u) |
Subtotal: 0 / 0 / 168 |
Irrep combinations (i,j,k,l) with indices: pos(A1g) ≤ i ≤ j ≤ k ≤ l ≤ pos(B3u) |
..16. |
A1gB1gB2gB3g. | ..24. |
A1gB1gA1uB1u. | ..48. |
A1gB1gB2uB3u. | ..16. |
A1gB2gA1uB2u. | ..72. |
A1gB2gB1uB3u. | ..12. |
A1gB3gA1uB3u. | ..24. |
A1gB3gB1uB2u. | ..12. |
B1gB2gA1uB3u. | ..24. |
B1gB2gB1uB2u. | ..4. |
B1gB3gA1uB2u. |
..18. |
B1gB3gB1uB3u. | ..6. |
B2gB3gA1uB1u. | ..12. |
B2gB3gB2uB3u. | ..18. |
A1uB1uB2uB3u. | | |
| |
| |
| |
| |
| |
Subtotal: 306 / 14 / 70 |
Total: 832 / 50 / 330 |
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