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Unformatted text preview: ergy orbital. Given the energy determined above, that makes the total energy 2α + 2β . Making the triplet will require removing one electron from the lowest energy orbital and moving it to the higher energy orbital (since we can’t have two electrons of the same spin in the same orbital). So, now we have the energy of each orbital taken once and added together, which gives α + β + α – β = 2α . The difference is 2β and that is the singlet-triplet splitting. For those interested in the chemistry, notice that this is, by definition of 2β , equal to the rotational barrier in ethylene. This is exactly what one expects, since the triplet has one electron in the bonding orbital and one in the antibonding, there is no net π bond, which is the same thing that happens at the rotational transition state: the π bond is destroyed. NAME: ________________________________________________________________ 7 A: nuclei 1 1 µ – " 2 # – $ Zk µ # 2 rk k R: Optimize molecular geometry? ' * 1 + $ P%& ) (µ# %&) – (µ% #&) , ( + 2 %& B:
! Choose a basis set 21
1sH a 1sH b where H and H are a b S: T: U:
"" a(1)b(2) 1 a(1)b(2) dr (1) dr (2) r12 C: D: the two H atoms in water
! Is new density matrix P(n) sufficiently similar to old density matrix P(n–1) ? –130.505 204 660 7 Compute and store all overlap, oneelectron, and two-electron integral...
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- Fall '08