Results for Point Group D4h



Characters of representations for molecular motions
Motion E 2C4 C2 2C'2 2C''2 i 2S4 σh v d
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 v d
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



Contributions to nonvanishing force field constants


pos(X) : Position of irreducible representation (irrep) X in character table of D4h

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


Calculate contributions to

A1g A2g B1g B2g Eg A1u A2u B1u B2u Eu
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Last update November, 13th 2023 by A. Gelessus, Impressum, Datenschutzerklärung/DataPrivacyStatement