Chapter 2, Problem 2G.7E

Interpretation Introduction

Interpretation:

The bond order and existence of ${\text{HeH}}^{-}$ has to be determined. Also, among ${\text{HeH}}^{-}$ and ${\text{HeH}}^{+}$ species with lowest energy has to be determined.

Concept Introduction:

Molecular orbital diagram is a linear combination of atomic orbitals of similar energy and similar symmetry. It is formed by the proper overlap of the atomic orbitals.

There are 3 types of molecular orbitals as follows:

1. 1. Bonding molecular orbital: They are formed by the constructive interference of atomic orbitals and electrons in it stabilize the molecule and are of lesser in energy.
2. 2. Antibonding molecular orbital: This type of orbitals increases the energy of molecule and destabilizes it and weakens the bond between the atoms.
3. 3. Non-bonding molecular orbital: These type of orbitals have energy similar to atomic orbitals that is addition or removal of electron does not changes the energy of molecule.

Bond order $b$ is defined as total number of bonds between the atoms. It is calculated as follows:

  $b=\frac{1}{2}\left[\begin{array}{l}\text{number of electrons in bonding orbitals}-\\ \text{number of electrons in antibonding orbitals}\end{array}\right]$        (1)