Chapter 14, Problem 14.20E

Interpretation Introduction

Interpretation:

The degeneracy of rotational levels for symmetric tops is proved to be $2\left(2J+1\right)$ if $K=0$, the degeneracy is $2J+1$.

Concept introduction:

In a molecule, the rotational energy level corresponds to the different probable ways in which the portion of a molecule rotates around the chemical bond that binds it to the rest of the molecule. Every rotational energy level possesses degeneracy.