Physical Chemistry MO Theory Description for the H2 Molecule Question

I’m working on a chemistry multi-part question and need guidance to help me learn.

Compare the MO theory description for the H2 molecule, where the wavefunction is given by equation a:

.ψ=[ψ (1)+ψ (1)][ψ (2)+ψ (2)]

$a.\psi =\left[{\psi }_A\right(1)+{\psi }_B(1\left)\right]\left[{\psi }_A\right(2)+{\psi }_B(2\left)\right]$

with the VB treatment given by equation b

$b.\psi ={\psi }_A\left(1\right){\psi }_B\left(2\right)+{\psi }_A\left(2\right){\psi }_B\left(1\right)+\lambda \left[{\psi }_A\right(1\left){\psi }_A\right(2)+{\psi }_B(1\left){\psi }_B\right(2\left)\right]$

1. What is the meaning of lambda, λ? [ Select ] [“The contribution of hybrid orbitals“, “The contribution of the molecular dipole“, “The contribution of functions describing ionic character“]

2. Under what condition(s) do the two equations become identical? [ Select ] [“λ>0 and λ<1“, “λ>1 and λ<0“, “λ=1“]

3. How does the MO theory treat the ionic character contribution to the wavefunction? [ Select ] [“The MO theory overestimates the ionic character“, “The MO theory underestimates the ionic character“, “The MO theory correctly estimates the ionic character contribution“]