Question

Atomic and molecular orbitals

a) What do graphical representations of orbitals typically show? How is this related to the statements often found in general chemistry textbooks about a large fraction of the electron density being enclosed in some three-dimensional surfaces ?

b) For many-electron atoms and molecules, why do we describe the electronic structure in terms of orbitals. Shouldn’t we just solve the Schrödinger equation and use the many-electron wavefunction instead?

c) In the context of orbital theory as taught in this course, what does ‘orbital occupation’ really mean?

d) State the Pauli principle in its most general form, and its consequences in molecular orbital theory.

e) Is there a unique set of molecular orbitals for a given molecule? Give a reason for your answer, not just Yes or No.

f) Describe an electronic configuration that cannot be correctly described with a single Slater-determinant wavefunction

g) In molecular orbital calculations based on the self-consistent field (SCF) concept, how are the orbital energies and the total energy related?

h) Describe an example for an unintuitive outcome when you change the occupation numbers of the orbitals of a system.