Klopman/Salem Equation ∆ E = Σ ab (q a + q b ) β ab S ab + Σ k<l Q k Q l ε R kl + Σ occ. r Σ unocc. s-Σ occ. s Σ unocc. r 2( Σ ab c ra c sb ab ) 2 E r- E s-first term second term third term q a and q b electron populations in atomic orbitals a and b β and S resonance and overlap integrals Q k and Q l total charges on atoms k and l ε local dielectric constant R kl distance between atoms k and l c ra c sb coefficient of atomic orbital a in molecular orbital r coefficient of atomic orbital b in molecular orbital s E r Energy of molecular orbital r E s Energy of molecular orbital s ∆ E = Simplified Form-Q nuc Q elec R + 2(c nuc c elec ) 2 E HOMO- E LUMO second term third term Hard nucleophiles have a low-energy HOMO and usually a negative charge Soft nucleophiles have a high-energy HOMO but no not necessarily have a negative charge
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This note was uploaded on 12/11/2009 for the course CHM Chm3120 taught by Professor Olgilvie during the Spring '09 term at University of Ottawa.