复旦大学：《物理化学》精品课程教学资源（PPT课件讲稿）第5章 多原子分子结构 Polyatomic Molecular Structure

four molecular orbitals are: v1=C11+C1H1 C22+C2H2 C33+C V4=C4O4+C4H4 2 3 20218/21 Chemistry Departme nt of Fudan University 11

Physical ChemistryI Chapter V Polyatomic Molecular Structure 2021/8/21 Chemistry Department of Fudan University 11 four molecular orbitals are: 1 C1 1 C 1 H1  =  + ' 2 2 2 2 2  =C  +C' H 3 C3 3 C 3 H3  =  + ' 4 C4 4 C 4 H4  =  + ' C1 = C2 = C3 = C4 1 2 3 4 C' = C' = C' = C

S5-1-3 Connection Conversion 1. vB theory is an approximate method, whereas Mo theory is quite accurate Localized orbital- No constant Energy Delocalized orbital--Energy Eigenvalue 20218/21 Chemistry Departme nt of Fudan University

Physical ChemistryI Chapter V Polyatomic Molecular Structure 2021/8/21 Chemistry Department of Fudan University 12 §5-1-3. Connection & Conversion 1. VB theory is an approximate method, whereas MO theory is quite accurate Delocalized orbital ⎯ Energy Eigenvalue Localized orbital ⎯ No constant Energy

2 Conversion between the two kinds of orbitals MO VB A1 CAS+CA中 C11+C"1 7p+Cr1(1)C 2+C2H2 +Crn,(2) C303+C V =Cp+C Br 3 Co+Ch 4 20218/21 Chemistry Departme nt of Fudan University

Physical ChemistryI Chapter V Polyatomic Molecular Structure 2021/8/21 Chemistry Department of Fudan University 13 2. Conversion between the two kinds of orbitals 1 1 ' A A C A A  = C s +  ' (1) T T2 p CT px C x  = +  ' (2) T T2 p CT py C y  = +  ' (3) T T2 p CT pz C z  = +  1 C1 1 C 1 H1  =  + ' 2 2 2 2 2  =C  +C' H 3 C3 3 C 3 H3  =  + ' 4 C4 4 C 4 H4  =  + ' MO VB CA =CT

Localized Bond length Molecular Binding energy, Orbital Charge density, etc Delocalized Molecular Spectrum Orbital 20218/21 Chemistry Departme nt of Fudan University 14

Physical ChemistryI Chapter V Polyatomic Molecular Structure 2021/8/21 Chemistry Department of Fudan University 14 Localized Molecular Orbital Delocalized Molecular Orbital Spectrum Bond length, Binding energy, Charge density, etc

85-2 Conjugate Molecules The particular characters of the conjugate molecules .The length of the bond is between the double bond and the single bond; ° Reactivity .The stability to the heat 20218/21 Chemistry Departme nt of Fudan University

Physical ChemistryI Chapter V Polyatomic Molecular Structure 2021/8/21 Chemistry Department of Fudan University 15 §5-2.Conjugate Molecules The particular characters of the conjugate molecules: •The length of the bond is between the double bond and the single bond; •Reactivity •The stability to the heat