Chapter 11, Problem 11D.3ST

Interpretation Introduction

Interpretation:

The conclusion has to be given for the observation of band in photoelectron spectrum of water near $7.0eV$ showing a long vibrational series with spacing $0.125eV$ and the occurrence of bending modes of water at $1596c{m}^{-1}$.

Concept Introduction:

The symmetry of $H_{2}O$ is $C_{2V}$ and has a bent structure.  The molecular orbitals are mainly formed from the p orbital of oxygen atoms.  One molecular orbital that is perpendicular to the plane of the molecule has a $b_1$ symmetry in $C_{2V}$.  The next p orbital is in the plane of the molecule and bisects the $HOH$ bond angle and it has $a_1$ symmetry. The occupancy of electron in $a_1$ molecular orbital determines the $HOH$ bond angle.  The third orbital is perpendicular to the other two orbitals and has  $b_2$ symmetry.

The modes of vibration of $H_{2}O$ are symmetric stretching, asymmetric stretching and bending.