Chapter 11, Problem 11D.1ST

Interpretation Introduction

Interpretation:

The infrared inactive normal modes in ${\text{CH}}_{\text{2}}={\text{CH}}_{\text{2}}$ has to be predicted.

Concept introduction:

The different types of vibrational motions in a molecule are described by normal modes of vibrations.  The total number of vibrational degrees of freedom for nonlinear molecule is represented by $3N-6$.  The total number of vibrational degrees of freedom for linear molecule is represented by $3N-5$.