. φN | Linear Variational Procedure: φi = µ ciµ χµ Minimal Basis: µ ≡ electron. χµ atom centered. χν |χµ = Sνµ is key. Example: H+ 2 . χ1 ≡ 1sa , χ2 ≡ 1sb : φ = 1 √ 2(1+S12) (1sa + 1sb ){α, β}. Ψ ≡ φ{α, β}. How to define bonding parameters? Partitioning charges: Mulliken analysis ρ(r1 , r1 ) = N Ψ∗(r1 , . . . , rN )Ψ(r1 , . . . , rN )dr2 . . . drN ρ(r, r) = ρ(r) = i φ∗ i (r)φi (r) = µν Pµν χ∗ ν (r)χµ (r) Pµν = i ciµc∗ iν . N = ρ(r)dr = µν Pµν Sνµ = Tr(PS) = µ (PS)µµ . Na = µ∈a (PS)µµ PS = 1 2(1 + S) 1 1 1 1 1 S S 1 = 1/2 1/2 1/2 1/2 Building orthogonal χ’s, φi = µ ciµ χµ Na = µ∈a Pµµ = ˆ Pa ρ(r)dr = a ρ(r)dr = i a dr φ∗ i φi = i Sa ii AMP (QCG@UniOvi) M2 2013 Sep 2013 3 / 6