Chapter 11, Problem 11B.3P

Interpretation Introduction

Interpretation:

The separation of pure rotational spectrum lines has to be calculated as a frequency and a wavenumber.  The value of $B$ is consistent with a $\text{N}-\text{H}$ bond length of $\text{101}\text{.4}\text{pm}$ and bond angle of $106.78°$ has to be shown.

Concept introduction:

The moment of inertia of a molecule about an axis passing through the centre of mass is directly proportional to the reduced mass of the molecule and the bond length of the molecule.  The rotational energy of a molecule is usually expressed in terms of its rotational constant.  The rotational constant of a molecule depends upon the moment of inertia of the molecule.