Chapter 11, Problem 11F.5P

(a)

Interpretation Introduction

Interpretation:

The observation corresponding to the fact that the ejection of the $\text{σ}$ electron is accompanied by a lot of vibrational excitation has to be explained.

Concept introduction:

An electronic state of energy has its own vibrational states.  The energy between the electronic states is large, followed by vibrational states and then rotational states.  During an electronic transition, electron from ground state moves straight to the excited state keeping the internuclear distance constant.  This is known as the Franck-Condon principle.

(b)

Interpretation Introduction

Interpretation:

The way in which the lack of much vibrational structure in the other band is consistent with the nonbonding role of ${\text{Br4p}}_x$ and ${\text{Br4p}}_y$ lone pair electrons has to be explained.

Concept introduction:

As mentioned in the concept introduction in part (a).