# Physical Chemistry MO Theory Description for the H2 Molecule Question

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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)]

$a.\psi =\left[{\psi }_{A}\left(1\right)+{\psi }_{B}\left(1\right)\right]\left[{\psi }_{A}\left(2\right)+{\psi }_{B}\left(2\right)\right]$

with the VB treatment given by equation b

$b.\psi ={\psi }_{A}\left(1\right){\psi }_{B}\left(2\right)+{\psi }_{A}\left(2\right){\psi }_{B}\left(1\right)+\lambda \left[{\psi }_{A}\left(1\right){\psi }_{A}\left(2\right)+{\psi }_{B}\left(1\right){\psi }_{B}\left(2\right)\right]$

1. What is the meaning of lambda, λ?

2. Under what condition(s) do the two equations become identical?

3. How does the MO theory treat the ionic character contribution to the wavefunction?