atom-bond polarizability
A quantity used in perturbation HMO theory as a measure of the change in electron density, q, of atom m caused by a change in the resonance integral, β, of bond r s: \[\pi _{\text{m,rs}}=\frac{\partial q_{\text{m}}}{\partial \beta _{\text{rs}}}\]
PAC, 1999, 71, 1919. 'Glossary of terms used in theoretical organic chemistry' on page 1924 (