Molecular Force Fields and Valency

摘要: The study of intramolecular force fields for small nuclear displacements provides a means extending our knowledge and understanding valency. For the chemist, most useful expression field is in terms bond-length changes bond-angle changes. quadratic form then $$ 2V = \sum\limits_i {{k_i}\Delta r_i^2 + \sum\limits_{ij} {{k_{ij}}\Delta r{}_i\Delta {r_j} \sum\limits_p {{k_p}\Delta \alpha _p^2 \sum\limits_{pq} {{k_{pq}}\Delta {\alpha _p}\Delta _q} \sum\limits_{ip} {{k_{ip}}\Delta {r_i}\Delta _p}} } $$ (1.1) where summation over all bonds interbond angles; Δr i r - ei , where equilibrium length ith bond, Δα p α ep value pth angle. There are two types constants equation (1.1): main k (bond) (angle), interaction ij (bond-bond), pq (angle-angle) ip (bond-angle).