7: Hydrogen Ion and Covalent Bonding Last updated Sep 18, 2020 Save as PDF 6.5: Strong force - Two state system or degenerate perturbation 7.1: Introduction Page ID28787 Graeme AcklandUniversity of Edinburgh ( \newcommand{\kernel}{\mathrm{null}\,}\) 7.1: Introduction7.2: Born-Oppenheimer Approximation7.3: The Electronic Ground State7.4: Rotational and Vibrational Modes7.5: Electronic States of the H₂ Molecule