Characters of representations for molecular motions
Motion |
E |
2C4 |
C2 |
2C'2 |
2C''2 |
i |
2S4 |
σh |
2σv |
2σd |
Cartesian 3N |
24 |
0 |
0 |
-4 |
0 |
0 |
0 |
8 |
4 |
0 |
Translation (x,y,z) |
3 |
1 |
-1 |
-1 |
-1 |
-3 |
-1 |
1 |
1 |
1 |
Rotation (Rx,Ry,Rz) |
3 |
1 |
-1 |
-1 |
-1 |
3 |
1 |
-1 |
-1 |
-1 |
Vibration |
18 |
-2 |
2 |
-2 |
2 |
0 |
0 |
8 |
4 |
0 |
Decomposition to irreducible representations
Motion |
A1g |
A2g |
B1g |
B2g |
Eg |
A1u |
A2u |
B1u |
B2u |
Eu |
Total |
Cartesian 3N |
2 |
2 |
2 |
2 |
2 |
0 |
2 |
0 |
2 |
4 |
18 |
Translation (x,y,z) |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
1 |
2 |
Rotation (Rx,Ry,Rz) |
0 |
1 |
0 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
2 |
Vibration |
2 |
1 |
2 |
2 |
1 |
0 |
1 |
0 |
2 |
3 |
14 |
Molecular parameter
Number of Atoms (N) |
8
|
Number of internal coordinates |
18
|
Number of independant internal coordinates |
2
|
Number of vibrational modes |
14
|
Force field analysis
Allowed / forbidden vibronational transitions
Operator |
A1g |
A2g |
B1g |
B2g |
Eg |
A1u |
A2u |
B1u |
B2u |
Eu |
Total |
Linear (IR) |
2 |
1 |
2 |
2 |
1 |
0 |
1 |
0 |
2 |
3 |
4 / 10 |
Quadratic (Raman) |
2 |
1 |
2 |
2 |
1 |
0 |
1 |
0 |
2 |
3 |
7 / 7 |
IR + Raman |
- - - - |
1 |
- - - - |
- - - - |
- - - - |
0 |
- - - - |
0 |
2 |
- - - - |
0* / 3 |
* Parity Mutual Exclusion Principle
Characters of force fields
(Symmetric powers of vibration representation)
Force field |
E |
2C4 |
C2 |
2C'2 |
2C''2 |
i |
2S4 |
σh |
2σv |
2σd |
linear |
18 |
-2 |
2 |
-2 |
2 |
0 |
0 |
8 |
4 |
0 |
quadratic |
171 |
3 |
11 |
11 |
11 |
9 |
1 |
41 |
17 |
9 |
cubic |
1.140 |
-4 |
20 |
-20 |
20 |
0 |
0 |
160 |
48 |
0 |
quartic |
5.985 |
9 |
65 |
65 |
65 |
45 |
5 |
525 |
133 |
45 |
quintic |
26.334 |
-14 |
110 |
-110 |
110 |
0 |
0 |
1.512 |
308 |
0 |
sextic |
100.947 |
19 |
275 |
275 |
275 |
165 |
5 |
3.941 |
693 |
165 |
Decomposition to irreducible representations
Column with number of nonvanshing force constants highlighted
Force field |
A1g |
A2g |
B1g |
B2g |
Eg |
A1u |
A2u |
B1u |
B2u |
Eu |
linear |
2 |
1 |
2 |
2 |
1 |
0 |
1 |
0 |
2 |
3 |
quadratic |
21 |
9 |
15 |
13 |
16 |
8 |
9 |
7 |
9 |
24 |
cubic |
88 |
76 |
84 |
82 |
120 |
56 |
68 |
52 |
74 |
160 |
quartic |
454 |
377 |
423 |
401 |
680 |
337 |
349 |
331 |
353 |
800 |
quintic |
1.784 |
1.707 |
1.760 |
1.738 |
3.089 |
1.518 |
1.595 |
1.494 |
1.626 |
3.467 |
sextic |
6.762 |
6.410 |
6.646 |
6.514 |
12.112 |
6.033 |
6.110 |
6.002 |
6.134 |
13.056 |
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
4h
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(Eu) |
..3. |
A1gA1g. | ..1. |
A2gA2g. | ..3. |
B1gB1g. | ..3. |
B2gB2g. | ..1. |
EgEg. | ..1. |
A2uA2u. | ..3. |
B2uB2u. | ..6. |
EuEu. | | |
| |
Subtotal: 21 / 8 / 10 |
Irrep combinations (i,j) with indices: pos(A1g) ≤ i ≤ j ≤ pos(Eu) |
Subtotal: 0 / 0 / 45 |
Total: 21 / 8 / 55 |
Contributions to nonvanishing cubic force field constants
Irrep combinations (i,i,i) with indices: pos(A1g) ≤ i ≤ pos(Eu) |
..4. |
A1gA1gA1g. | | |
| |
| |
| |
| |
| |
| |
| |
| |
Subtotal: 4 / 1 / 10 |
Irrep combinations (i,i,j) (i,j,j) with indices: pos(A1g) ≤ i ≤ j ≤ pos(Eu) |
..2. |
A1gA2gA2g. | ..6. |
A1gB1gB1g. | ..6. |
A1gB2gB2g. | ..2. |
A1gEgEg. | ..2. |
A1gA2uA2u. | ..6. |
A1gB2uB2u. | ..12. |
A1gEuEu. | ..3. |
A2gEuEu. | ..2. |
B1gEgEg. | ..12. |
B1gEuEu. |
..2. |
B2gEgEg. | ..12. |
B2gEuEu. | | |
| |
| |
| |
| |
| |
| |
| |
Subtotal: 67 / 12 / 90 |
Irrep combinations (i,j,k) with indices: pos(A1g) ≤ i ≤ j ≤ k ≤ pos(Eu) |
..4. |
A2gB1gB2g. | ..4. |
B1gA2uB2u. | ..3. |
EgA2uEu. | ..6. |
EgB2uEu. | | |
| |
| |
| |
| |
| |
Subtotal: 17 / 4 / 120 |
Total: 88 / 17 / 220 |
Contributions to nonvanishing quartic force field constants
Irrep combinations (i,i,i,i) with indices: pos(A1g) ≤ i ≤ pos(Eu) |
..5. |
A1gA1gA1gA1g. | ..1. |
A2gA2gA2gA2g. | ..5. |
B1gB1gB1gB1g. | ..5. |
B2gB2gB2gB2g. | ..2. |
EgEgEgEg. | ..1. |
A2uA2uA2uA2u. | ..5. |
B2uB2uB2uB2u. | ..36. |
EuEuEuEu. | | |
| |
Subtotal: 60 / 8 / 10 |
Irrep combinations (i,i,i,j) (i,j,j,j) with indices: pos(A1g) ≤ i ≤ j ≤ pos(Eu) |
Subtotal: 0 / 0 / 90 |
Irrep combinations (i,i,j,j) with indices: pos(A1g) ≤ i ≤ j ≤ pos(Eu) |
..3. |
A1gA1gA2gA2g. | ..9. |
A1gA1gB1gB1g. | ..9. |
A1gA1gB2gB2g. | ..3. |
A1gA1gEgEg. | ..3. |
A1gA1gA2uA2u. | ..9. |
A1gA1gB2uB2u. | ..18. |
A1gA1gEuEu. | ..3. |
A2gA2gB1gB1g. | ..3. |
A2gA2gB2gB2g. | ..1. |
A2gA2gEgEg. |
..1. |
A2gA2gA2uA2u. | ..3. |
A2gA2gB2uB2u. | ..6. |
A2gA2gEuEu. | ..9. |
B1gB1gB2gB2g. | ..3. |
B1gB1gEgEg. | ..3. |
B1gB1gA2uA2u. | ..9. |
B1gB1gB2uB2u. | ..18. |
B1gB1gEuEu. | ..3. |
B2gB2gEgEg. | ..3. |
B2gB2gA2uA2u. |
..9. |
B2gB2gB2uB2u. | ..18. |
B2gB2gEuEu. | ..1. |
EgEgA2uA2u. | ..3. |
EgEgB2uB2u. | ..18. |
EgEgEuEu. | ..3. |
A2uA2uB2uB2u. | ..6. |
A2uA2uEuEu. | ..18. |
B2uB2uEuEu. | | |
| |
Subtotal: 195 / 28 / 45 |
Irrep combinations (i,i,j,k) (i,j,j,k) (i,j,k,k) with indices: pos(A1g) ≤ i ≤ j ≤ k ≤ pos(Eu) |
..2. |
EgEgA2uB2u. | ..6. |
A1gA2gEuEu. | ..4. |
A1gB1gEgEg. | ..24. |
A1gB1gEuEu. | ..4. |
A1gB2gEgEg. | ..24. |
A1gB2gEuEu. | ..2. |
A2gB1gEgEg. | ..12. |
A2gB1gEuEu. | ..2. |
A2gB2gEgEg. | ..12. |
A2gB2gEuEu. |
..12. |
B1gB2gEuEu. | ..12. |
A2uB2uEuEu. | | |
| |
| |
| |
| |
| |
| |
| |
Subtotal: 116 / 12 / 360 |
Irrep combinations (i,j,k,l) with indices: pos(A1g) ≤ i ≤ j ≤ k ≤ l ≤ pos(Eu) |
..8. |
A1gA2gB1gB2g. | ..8. |
A1gB1gA2uB2u. | ..6. |
A1gEgA2uEu. | ..12. |
A1gEgB2uEu. | ..4. |
A2gB2gA2uB2u. | ..3. |
A2gEgA2uEu. | ..6. |
A2gEgB2uEu. | ..6. |
B1gEgA2uEu. | ..12. |
B1gEgB2uEu. | ..6. |
B2gEgA2uEu. |
..12. |
B2gEgB2uEu. | | |
| |
| |
| |
| |
| |
| |
| |
| |
Subtotal: 83 / 11 / 210 |
Total: 454 / 59 / 715 |
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Last update November, 13th 2023 by A. Gelessus, Impressum, Datenschutzerklärung/DataPrivacyStatement