The Polarization Propagator Approach as a Tool to Study Electronic Molecular Structures from High-Resolution NMR Parameters

GUSTAVO A. AUCAR; MARTÍN RUIZ DE AZÚA; CLAUDIA G. GIRIBET

High Resolution NMR Spectroscopy: Understanding Molecules and their Electronic Structures

Elsevier

Año: 2013; p. 119 - 158

Chapter Outline 1. Introduction 120 2. General Theory 121 2.1. Propagators: Definition and Their Relation to Rayleigh?Schro¨dinger Perturbation Theory 121 2.2. The PP at Random Phase Approximation Level of Approach 122 2.3. The CLOPPA and IPPP Approaches 126 2.4. Zeroth-Order of the Principal Propagator Approach and the Pople?Santry Model 130 3. Applications 132 3.1. The Deep Quantum Origin of the Karplus Rule 132 3.2. The Sign of the NMR J Couplings 135 3.3. The s?p Decomposition of the FC Term of J Couplings 139 3.4. CLOPPA Analysis of General Features of 1J(X, Y) Couplings 140 3.5. Enhancement of J Coupling by Hyperconjugation 144 3.6. Ab Initio CLOPPA Decomposition: Examples 148 4. Appendix: Derivation of the Coupled HF Equations 155 5. Problems 156 References 158