The symmetry labels of the H -like f orbitals in D 4h symmetry is to be determined. Concept introduction: The characters of the irreducible representations of the given point group can be multiplied by each other. The only condition is the characters of the same symmetry operations are multiplied together. The multiplication of the characters is commutative. The great orthogonality theorem for the reducible representation can be represented as, a Γ = 1 h ∑ all classes of point group N ⋅ χ Γ ⋅ χ linear combo Where, • a Γ is the number of times the irreducible representation appears in a linear combination. • h is the order of the group. • χ Γ is the character of the class of the irreducible representation. • χ linear combo is the character of the class linear combination. • N is the number of symmetry operations.

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Answer 1

Question

Chapter 13, Problem 13.70E

Interpretation Introduction

Interpretation:

The symmetry labels of the H-like f orbitals in D4h symmetry is to be determined.

Concept introduction:

The characters of the irreducible representations of the given point group can be multiplied by each other. The only condition is the characters of the same symmetry operations are multiplied together. The multiplication of the characters is commutative.

The great orthogonality theorem for the reducible representation can be represented as,

aΓ=1h∑all classesof point groupN⋅χΓ⋅χlinear combo

Where,

• aΓ is the number of times the irreducible representation appears in a linear combination.

• h is the order of the group.

• χΓ is the character of the class of the irreducible representation.

• χlinear combo is the character of the class linear combination.

• N is the number of symmetry operations.

Expert Solution & Answer

Answer to Problem 13.70E

The symmetry labels of the H-like f orbitals in D4h symmetry are A2u, B1u, B2u and Eu.

Explanation of Solution

The formula to calculate the value of χC2 is,

χC2=1+2cosθ+2cos2θ+2cos3θ …(1)

Substitute the value of θ=180° in equation (1).

χC2=1+2cos180°+2cos2(180°)+2cos3(180°)=1−2+2−2=−1

The formula to calculate the value of χC4 is,

χC4=1+2cosθ+2cos2θ+2cos3θ …(2)

Substitute the value of θ=90° in equation (2).

χC4=1+2cos90°+2cos2(90°)+2cos3(90°)=1+0−2+0=−1

The formula to calculate the value of χS4 is,

χS4=−1+2cosθ−2cos2θ+2cos3θ …(3)

Substitute the value of θ=90° in equation (3).

χS4=−1+2cos90°−2cos2(90°)+2cos3(90°)=−1+0+2+0=1

Therefore, the character table for f orbital is shown below.

E2C4C22C2'2C2''i2S4σh2σv2σdΓ7−1−1−1−1−71111

The great orthogonality theorem for the reducible representation can be represented as,

aΓ=1h∑all classesof point groupN⋅χΓ⋅χlinear combo

Where,

• aΓ is the number of times the irreducible representation appears in a linear combination.

• h is the order of the group.

• χΓ is the character of the class of the irreducible representation.

• χlinear combo is the character of the class linear combination.

• N is the number of symmetry operations.

The order of the group is 16.

Substitute the value of order of the group, character of the class of the irreducible representation from character table of D4h point group, character of the class linear combination and number of symmetry operations for A1g.

aA1g=116[(1⋅1⋅7)+(2⋅1⋅−1)+(1⋅1⋅−1)+(2⋅1⋅−1)+(2⋅1⋅−1)+(1⋅1⋅−7)+(2⋅1⋅1)+(1⋅1⋅1)+(2⋅1⋅1)+(2⋅1⋅1)]=0

The number of times the irreducible representation for A1g appears in a linear combination is 0.

Similarly, for A2g, substitute the value of order of the group, character of the class of the irreducible representation from character table of D4h point group, character of the class linear combination and number of symmetry operations.

aA2g=116[(1⋅1⋅7)+(2⋅1⋅−1)+(1⋅1⋅−1)+(2⋅−1⋅−1)+(2⋅−1⋅−1)+(1⋅1⋅−7)+(2⋅1⋅1)+(1⋅1⋅1)+(2⋅−1⋅1)+(2⋅−1⋅1)]=0

The number of times the irreducible representation for A2g appears in a linear combination is 0.

Similarly, for B1g, substitute the value of order of the group, character of the class of the irreducible representation from character table of D4h point group, character of the class linear combination and number of symmetry operations.

aB1g=116[(1⋅1⋅7)+(2⋅−1⋅−1)+(1⋅1⋅−1)+(2⋅1⋅−1)+(2⋅−1⋅−1)+(1⋅1⋅−7)+(2⋅−1⋅1)+(1⋅1⋅1)+(2⋅1⋅1)+(2⋅−1⋅1)]=0

The number of times the irreducible representation for B1g appears in a linear combination is 0.

Similarly, for B2g, substitute the value of order of the group, character of the class of the irreducible representation from character table of D4h point group, character of the class linear combination and number of symmetry operations.

aB2g=116[(1⋅1⋅7)+(2⋅−1⋅−1)+(1⋅1⋅−1)+(2⋅−1⋅−1)+(2⋅1⋅−1)+(1⋅1⋅−7)+(2⋅−1⋅1)+(1⋅1⋅1)+(2⋅−1⋅1)+(2⋅1⋅1)]=0

The number of times the irreducible representation for B2g appears in a linear combination is 0.

Similarly, for Eg, substitute the value of order of the group, character of the class of the irreducible representation from character table of D4h point group, character of the class linear combination and number of symmetry operations.

aEg=116[(1⋅2⋅7)+(2⋅0⋅−1)+(1⋅−2⋅−1)+(2⋅0⋅−1)+(2⋅0⋅−1)+(1⋅2⋅−7)+(2⋅0⋅1)+(1⋅−2⋅1)+(2⋅0⋅1)+(2⋅0⋅1)]=0

The number of times the irreducible representation for Eg appears in a linear combination is 0.

Similarly, for A1u, substitute the value of order of the group, character of the class of the irreducible representation from character table of D4h point group, character of the class linear combination and number of symmetry operations.

aA1u=116[(1⋅1⋅7)+(2⋅1⋅−1)+(1⋅1⋅−1)+(2⋅1⋅−1)+(2⋅1⋅−1)+(1⋅−1⋅−7)+(2⋅−1⋅1)+(1⋅−1⋅1)+(2⋅−1⋅1)+(2⋅−1⋅1)]=0

The number of times the irreducible representation for A1u appears in a linear combination is 0.

Similarly, for A2u, substitute the value of order of the group, character of the class of the irreducible representation from character table of D4h point group, character of the class linear combination and number of symmetry operations.

aA2u=116[(1⋅1⋅7)+(2⋅1⋅−1)+(1⋅1⋅−1)+(2⋅−1⋅−1)+(2⋅−1⋅−1)+(1⋅−1⋅−7)+(2⋅−1⋅1)+(1⋅−1⋅1)+(2⋅1⋅1)+(2⋅1⋅1)]=1

The number of times the irreducible representation for A2u appears in a linear combination is 1.

Similarly, for B1u, substitute the value of order of the group, character of the class of the irreducible representation from character table of D4h point group, character of the class linear combination and number of symmetry operations.

aB1u=116[(1⋅1⋅7)+(2⋅−1⋅−1)+(1⋅1⋅−1)+(2⋅1⋅−1)+(2⋅−1⋅−1)+(1⋅−1⋅−7)+(2⋅1⋅1)+(1⋅−1⋅1)+(2⋅−1⋅1)+(2⋅1⋅1)]=1

The number of times the irreducible representation for B1u appears in a linear combination is 1.

Similarly, for B2u, substitute the value of order of the group, character of the class of the irreducible representation from character table of D4h point group, character of the class linear combination and number of symmetry operations.

aB2u=116[(1⋅1⋅7)+(2⋅−1⋅−1)+(1⋅1⋅−1)+(2⋅−1⋅−1)+(2⋅1⋅−1)+(1⋅−1⋅−7)+(2⋅1⋅1)+(1⋅−1⋅1)+(2⋅1⋅1)+(2⋅−1⋅1)]=1

The number of times the irreducible representation for B2u appears in a linear combination is 1.

Similarly, for Eu, substitute the value of order of the group, character of the class of the irreducible representation from character table of D4h point group, character of the class linear combination and number of symmetry operations.

aEu=116[(1⋅2⋅7)+(2⋅0⋅−1)+(1⋅−2⋅−1)+(2⋅0⋅−1)+(2⋅0⋅−1)+(1⋅−2⋅−7)+(2⋅0⋅1)+(1⋅2⋅1)+(2⋅0⋅1)+(2⋅0⋅1)]=2

The number of times the irreducible representation for Eu appears in a linear combination is 2.

Conclusion

The symmetry labels of the H-like f orbitals in D4h symmetry are A2u, B1u, B2u and Eu.

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