Chapter 11, Problem 11B.10P

(a)

Interpretation Introduction

Interpretation:

An expression for the wave numbers of allowed rotational transitions has to be stated.

Concept introduction:

A rotational spectrum is a spectrum in which only the rotation of molecule changes.  For a molecule to exhibit pure rotational spectrum, the molecule must possess a permanent electric dipole moment.  The molecules on rotation tend to experience a centrifugal force, this centrifugal force brings about a change in the molecular geometry and the moment of inertia of molecule.  This centrifugal distortion affects the energy relation to give the equation as shown below.

  $\tilde{F}\left(J\right)=\tilde{B}J(J+1)-{\tilde{D}}_J{J}^2{\left(J+1\right)}^2$.

(b)

Interpretation Introduction

Interpretation:

The values of constants $B$, $D_J$ and $D_{JK}$ have to be stated.

Concept introduction:

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