Chemistry Reference
In-Depth Information
The van der Waals Bond
4.1 Introduction
4.2 Elements of Rayleigh-Schr
€
odinger (RS) Perturbation Theory
4.3 Molecular Interactions
4.3.1 Non-expanded Energy Corrections up to Second Order
4.3.2 Expanded Energy Corrections up to Second Order
4.4 The Two-state Model of Long-range Interactions
4.5 The van der Waals Interactions
4.5.1 Atom-Atom Dispersion
4.5.2 Atom-Linear Molecule Dispersion
4.5.3 Atom-Linear Dipolar Molecule
10
Induction
4.6 The C
6
Dispersion Coefficient for the H-H Interaction
4.7 The van der Waals Bond
4.8 The Keesom Interaction
4.1 INTRODUCTION
In the previous chapters we sketched an elementary model of the chemical
bond occurring between atoms in terms of a simple H
€
uckel theory mostly
involving solution of 2
2 secular equations. The theory, first concerned
with
s
-bonding in H
2
He
2
;
H
2
;
;
He
2
, was next extended to
s
- and
p
-bonding in first-rowhomonuclear diatomics and to the study ofmultiple
bonds, the fundamental quantity being a bond integral
b
, whose form is
