[PoetryInMotion]

Hi!

I am supposed to determine the LUMO and HOMO of hydrogen perodixde and DME and also which LUMO and HOMO that is higher in energy. This is what I have come up with this far:

Hydrogen peroxide
σ_O-O (much lower than sp3 for oxygen)
σ_O-H (lower than 1s for hydrogen)
sp³_O (non bonding pairs)
σ*_O-O (much higher than sp3 for oxygen)
σ*_O-H (higher than sp3 for oxygen)

Conclusions: σ*_O-H is LUMO. The free pairs of the oxygen are the HOMOs.

DMO
σ_C-O (lower than sp3 for oxygen)
σ_C-H (lower than 1s for hydrogen)
sp³_O (non bonding pairs)
σ*_C-O (relatively much higher than sp3 for carbon)
σ*_C-H (higher than sp3 for carbon)

Conclusions: σ*_C-H is LUMO. The free pair of the oxygen are still HOMOs.

However, the solutions we have been given says that σ*_O-O and σ*_C-O are the LUMOs. So, what's wrong this far? And how should I determine which is the highest LUMO and highest HOMO?