Chapter 11, Problem 11C.5ST

Interpretation Introduction

Interpretation:

Infrared inactive normal mode in $C_6{H}_6$ has to be identified.

Concept Introduction:

Normal modes are independent and synchronous motion of atoms or a group of atoms that taking place in a molecule without causing the excitation of other modes.

Selection rule for vibrational spectrum:

During the vibration, the electric dipole moment of the molecule should change.

Gross selection rule for a normal mode to be infrared activity:

A normal mode is infrared active, if the motion causes the electric dipole moment of the molecule to change.