darkol933

Great, thanks. When I think about it, it makes sense. The molecular orbital is at lower energy state than the atomic orbitals alone, so the extra energy is released via photons.

When 2 hydrogen atoms bond to create H2 molecule, their atomic orbitals interfere to create a molecular orbital. Since hydrogen has 1 electron, there will be 2 electrons in H2 molecule. If they are in the same orbital, I assume they must have anti-parallel spins -- +1/2 and -1/2. So, my question is: ''How does an electron reverse its spin?''. If two hydrogen atoms have electrons with same spin, say +1/2, how does one of them 'reverse'? I thought that there is a conservation of total spin, so I guess that the electron might emit a photon (spin 1)?