Class Summary          10/01/04

 

Referring back to Bond Dissociation Enthalpies, Radical Stability, etc.

 

Another paper by Zavitsas

 

Matsunaga, N., Rogers, D.W. and Zavitsas, A.A.  Pauling’s Electronegativity Equation and a New Corollary Accurateyl Predict Bond Dissociation Enthalpies and Enhance Current Understanding of the Nature of the Chemical Bond  J. Org. Chem. (2003) 68, 3158-3172.

 

10/01   Wavefunctions for Open-Shell Systems

 

YROHF = y1(1)a(1)y1(2)b(2)y2(3)a(3)y2(4)b(4) ... yn/2(n)a(n)

 

YUHF = y1a(1)a(1)y1b(2)b(2)y2a(3)a(3)y2b(4)b(4) ... yn/2(n)a(n)

 

Spin Polarization

In an open-shell system where there is a singly occupied a-orbital, the rest of the electrons will polarize spin to get a near that center.

 

Why not use UHF all of the time?

            COST OF UHF:          SPIN CONTAMINATION

                                                Physically unrealistic

UHF must give an Eignfunction of <sz>, but does NOT have to give an Eigenfunction of the <s2> operator

 

 

HANDOUTS HANDED OUT IN CLASS ON 10/01/04

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