The procedure can be introduced by considering the H2 molecule. Its molecular orbitals are constructed from the valence-shell orbitals of each hydrogen atom, which are the 1s orbitals of the atoms. Two superpositions of these two orbitals can be formed, one by summing the orbitals and the other by taking their difference. In the former, the amplitudes of the two atomic orbitals interfere constructively with one another, and there is consequently an enhanced amplitude between the two nuclei. As a result, any electron that occupies this molecular orbital has a high probability of being found between the two nuclei, and ...(100 of 27318 words)