Chapter 11, Problem 11E.2P

(i)

Interpretation Introduction

Interpretation:

The number of normal modes of vibration in linear ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$ has to be stated.

Concept introduction:

The complex vibrations exhibit by the polyatomic molecule is known as normal modes of vibrations.  The vibrational modes of a molecule are IR or Raman active.  If a molecule has centre of symmetry, then the modes which are IR-active will be Raman inactive and the modes that are IR-inactive will be Raman active.  The total number of vibrational degrees of freedom for linear molecule is represented by $3N-5$.

(ii)

Interpretation Introduction

Interpretation:

The symmetry point groups of the three proposed conformations of nonlinear ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$ have to be stated.

Concept introduction:

The group of symmetry operations of which at least one point is kept fixed is known as point group.  The symmetry operations can be identity, rotation, reflection, inversion and improper rotation.

(iii)

Interpretation Introduction

Interpretation:

The conformations out of proposed conformations which are inconsistent with the spectroscopic data have to be determined.

Concept introduction:

As mentioned in the concept introduction in part (ii).