I am learning about orbitals and bonding and antibonding MOs. So far, I know that when you combine s orbitals, you form both bonding and antibonding MOs- bonding when the wavefunctions are added in phase and antibonding when added out of phase. I have had several questions along the way:
- What is the significance, if any, of the phase of the wavefunction for electrons in atoms when the atom is not interacting? Suppose you had a free hydrogen atom in space. Would it make a difference if you switched the phase of its 1s orbital? What about if you had a multi-electron atom? Would there be a consequence of switching the phase of the 1s orbital but not of the other orbitals? My guess is that, if this is at all possible, then yes this would make a difference due to the penetration of higher orbitals- i.e. the 2s orbital has some penetration into the 1s orbital. Thinking about it in this way, I think atoms are most stable when all the s orbitals are in the same phase and the p orbital phases are aligned. Otherwise you would get cancellation of the wavefucntion in regions closer to the nucleus so the electrons would be found further out, and therefore would have a higher potential energy. There would also be more localisation of electrons further from the nucleus so they would have a higher kinetic energy too. I think it therefore would be significant when we change the phase of orbitals relative to other orbitals (whether in the same atom or in interacting atoms), but if you changed the phase of all wavefunctions in the universe right now then it wouldn't matter.
My second question:
- How do we form the bonding and antibonding MOs? Is it becaue each orbital is actually in a superposition of being 'phase 0' and 'phase pi' which is why you get both bonding and antibonding MOs? I'm just not sure if superposition of states is at all important here, or if I have misunderstood this.
Finally, when I was considering p orbitals, I noticed that th phase of the two lobes in a single p orbital is opposite.
- So here we have two opposite phases existing together. Is there a significance of this? Or is it perhaps again only important in the interaction of p orbitals?