Chemika Examenwiki - Gebruikersbijdragen [nl]

Chemical applications of group theory

2023-02-04T09:17:25Z

R0702077: /* Question 2 */

[[Categorie:Machemie]]
==Vakinformatie==
Given by professor Thomas Jagau in 2021-2022.

==Examenvragen==

===Exam 30th January===

====Question 1====
# Give the point group of 3 molecules
# Which molecules are chiral?

====Question 2====
Given is a multiplication table (6x6) like the one from exercise session 1 Q.1
# What is the order of the group?
# Is the group cyclic?
# Is the group abelian?
# What are the classes?

====Question 3====
# What are the irreps of the pz-orbitals of trimethylenemethane (D3h)?
# Derive the SALCs.
# Order the SALCs in terms of energy by looking at the amount of nodes.
# Derive the term symbols.

====Question 4====
# Perform a normal coordinate analysis on SF6 (Oh). What are the irreps of the translational, rotational and vibrational modes?
# Does removal of an electron from the HOMO (SF6+) affect the symmetry?

===Exam 20th January===
The exam is open book. You can take the book by prof. Ceulemans and the printed pages of the exercise sessions.

====Question 1 (6/20)====
# Give the point groups of 4 molecules.
# Construct the multiplication table of a D2h molecule.

====Question 2 (9/20)====
# Give the point group of allene.
# Construct the matrix representation for this point group looking at the 4 hydrogens.
# Perform a normal coordinate analysis. Give the irreps of the rotational, translational and vibrational displacements.
# Imagine a fully planar allene. Perform a normal coordinate analysis.
# Are these visible in the IR spectrum? If so, are they distinguishable?

====Question 3 (5/20)====
# Give the point group of C8F8, (synthesized in 2022 for the first time)
# Give the term symbols of the excitations HOMO --> LUMO and HOMO --> LUMO+1. The HOMO is a fully occupied t2u orbital and the LUMO and LUMO+1 are a1g and t1u respectively.
# Are these visible in the UV/VIS spectrum?

===Exam 26th August 2022===
The exam is open book. You can take the book by prof. Ceulemans and the printed pages of the exercise sessions.

====Question 1 (4/20)====
Given are the following equations:
*i*i=j*j=k*k=-e
*i*j*k=-e
# Is the group abelian. Explain your reasoning.
# Is the group cyclic. Explain your reasoning.

====Question 2 (10/20)====
Given is the molecule C4H2N2 (trans)
# What is the point group of this molecule?
# Do a full coordinate analyis. Give the irreps of the rotational, translational and vibrational displacements.
# What irreps will be visible in the IR spectrum?
# There are 10 pi-electrons. Give the irreps of the orbitals involved. (Unsure about this question, but it did involve the pi-system)
# The ground state evolves according to the totally symmetric irrep. What excitations would vibrationally couple with the ground state?

====Question 3 (6/20)====
ML6 with Oh point group and 8 d-electrons. (Similar to Q4 exercise session 5)
# Identify d-electron configuration of lowest energy state.
# Give the term symbols of the ground state. Start from the character table and work out the necessary direct products. No need to take spin into account.
# If we excite 1 electron give the term symbols. Take into account spin.
# What excitations would be optically visible.

Chemical applications of group theory

2023-02-04T09:11:24Z

R0702077: /* Question 3 */

[[Categorie:Machemie]]
==Vakinformatie==
Given by professor Thomas Jagau in 2021-2022.

==Examenvragen==

===Exam 30th January===

====Question 1====
# Give the point group of 3 molecules
# Which molecules are chiral?

====Question 2====
Given is a multiplication table not unlike the one from exercise session 1 Q.1
# Is the group cyclic?
# Is the group abelian?
# What are the classes?

====Question 3====
# What are the irreps of the pz-orbitals of trimethylenemethane (D3h)?
# Derive the SALCs.
# Order the SALCs in terms of energy by looking at the amount of nodes.
# Derive the term symbols.

====Question 4====
# Perform a normal coordinate analysis on SF6 (Oh). What are the irreps of the translational, rotational and vibrational modes?
# Does removal of an electron from the HOMO (SF6+) affect the symmetry?

===Exam 20th January===
The exam is open book. You can take the book by prof. Ceulemans and the printed pages of the exercise sessions.

====Question 1 (6/20)====
# Give the point groups of 4 molecules.
# Construct the multiplication table of a D2h molecule.

====Question 2 (9/20)====
# Give the point group of allene.
# Construct the matrix representation for this point group looking at the 4 hydrogens.
# Perform a normal coordinate analysis. Give the irreps of the rotational, translational and vibrational displacements.
# Imagine a fully planar allene. Perform a normal coordinate analysis.
# Are these visible in the IR spectrum? If so, are they distinguishable?

====Question 3 (5/20)====
# Give the point group of C8F8, (synthesized in 2022 for the first time)
# Give the term symbols of the excitations HOMO --> LUMO and HOMO --> LUMO+1. The HOMO is a fully occupied t2u orbital and the LUMO and LUMO+1 are a1g and t1u respectively.
# Are these visible in the UV/VIS spectrum?

===Exam 26th August 2022===
The exam is open book. You can take the book by prof. Ceulemans and the printed pages of the exercise sessions.

====Question 1 (4/20)====
Given are the following equations:
*i*i=j*j=k*k=-e
*i*j*k=-e
# Is the group abelian. Explain your reasoning.
# Is the group cyclic. Explain your reasoning.

====Question 2 (10/20)====
Given is the molecule C4H2N2 (trans)
# What is the point group of this molecule?
# Do a full coordinate analyis. Give the irreps of the rotational, translational and vibrational displacements.
# What irreps will be visible in the IR spectrum?
# There are 10 pi-electrons. Give the irreps of the orbitals involved. (Unsure about this question, but it did involve the pi-system)
# The ground state evolves according to the totally symmetric irrep. What excitations would vibrationally couple with the ground state?

====Question 3 (6/20)====
ML6 with Oh point group and 8 d-electrons. (Similar to Q4 exercise session 5)
# Identify d-electron configuration of lowest energy state.
# Give the term symbols of the ground state. Start from the character table and work out the necessary direct products. No need to take spin into account.
# If we excite 1 electron give the term symbols. Take into account spin.
# What excitations would be optically visible.

Chemical applications of group theory

2023-02-04T09:10:56Z

R0702077: /* Examenvragen */

[[Categorie:Machemie]]
==Vakinformatie==
Given by professor Thomas Jagau in 2021-2022.

==Examenvragen==

===Exam 30th January===

====Question 1====
# Give the point group of 3 molecules
# Which molecules are chiral?

====Question 2====
Given is a multiplication table not unlike the one from exercise session 1 Q.1
# Is the group cyclic?
# Is the group abelian?
# What are the classes?

====Question 3====
# What are the irreps of the pz-orbitals of trimethylenemethane (D3h)
# Derive the SALCs.
# Order the SALCs in terms of energy by looking at the amount of nodes.
# Derive the term symbols.

====Question 4====
# Perform a normal coordinate analysis on SF6 (Oh). What are the irreps of the translational, rotational and vibrational modes?
# Does removal of an electron from the HOMO (SF6+) affect the symmetry?

===Exam 20th January===
The exam is open book. You can take the book by prof. Ceulemans and the printed pages of the exercise sessions.

====Question 1 (6/20)====
# Give the point groups of 4 molecules.
# Construct the multiplication table of a D2h molecule.

====Question 2 (9/20)====
# Give the point group of allene.
# Construct the matrix representation for this point group looking at the 4 hydrogens.
# Perform a normal coordinate analysis. Give the irreps of the rotational, translational and vibrational displacements.
# Imagine a fully planar allene. Perform a normal coordinate analysis.
# Are these visible in the IR spectrum? If so, are they distinguishable?

====Question 3 (5/20)====
# Give the point group of C8F8, (synthesized in 2022 for the first time)
# Give the term symbols of the excitations HOMO --> LUMO and HOMO --> LUMO+1. The HOMO is a fully occupied t2u orbital and the LUMO and LUMO+1 are a1g and t1u respectively.
# Are these visible in the UV/VIS spectrum?

===Exam 26th August 2022===
The exam is open book. You can take the book by prof. Ceulemans and the printed pages of the exercise sessions.

====Question 1 (4/20)====
Given are the following equations:
*i*i=j*j=k*k=-e
*i*j*k=-e
# Is the group abelian. Explain your reasoning.
# Is the group cyclic. Explain your reasoning.

====Question 2 (10/20)====
Given is the molecule C4H2N2 (trans)
# What is the point group of this molecule?
# Do a full coordinate analyis. Give the irreps of the rotational, translational and vibrational displacements.
# What irreps will be visible in the IR spectrum?
# There are 10 pi-electrons. Give the irreps of the orbitals involved. (Unsure about this question, but it did involve the pi-system)
# The ground state evolves according to the totally symmetric irrep. What excitations would vibrationally couple with the ground state?

====Question 3 (6/20)====
ML6 with Oh point group and 8 d-electrons. (Similar to Q4 exercise session 5)
# Identify d-electron configuration of lowest energy state.
# Give the term symbols of the ground state. Start from the character table and work out the necessary direct products. No need to take spin into account.
# If we excite 1 electron give the term symbols. Take into account spin.
# What excitations would be optically visible.