Chapter 11, Problem 11C.5E

Interpretation Introduction

Interpretation:

Molecules that are infrared active has to be identified from the given molecules.

Concept Introduction:

Selection rule for vibrational spectrum:

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

• For homonuclear molecules, the stretching motion does not cause the electric dipole moment to change and hence are infrared inactive.
• For heteronuclear molecules, the stretching motion causes the electric dipole moment to change and hence are infrared active. However, not all the modes of these molecules are infrared active.