Coupling between bonds

Like MM2, MM-t includes coupling between bond stretching and angle bending. If the angle is defined to include atoms i, j, and k, where k is the central atom, then MM-t couples stretching of the ik and jk bonds with the angle ... 

Here is a constant that depends on the nature of atoms A, B and C. Not only that, both MM-f and MM2 allow for coupling between bond-stretching and angle-bending. Electrostatic interactions are accounted for by the interaction of bond dipoles rather than point charges. 

In the LM model, molecular vibrations are treated as motions of individual anharmonic bonds [38] (usually Morse oscillators). They therefore include anharmonicity, but not coupling between bonds, thus requiring inclusion of interbond coupling for obtaining a better description. For the case of t identical Morse oscillators, the energy levels related to the LM Hamiltonian are given by... 

Ritchie (2) suggested that the differences between the reactions that follow the Swain-Scott and the Ritchie equations stem from the coupling between bond formation and bond cleavage in the SN2 process as opposed to only... 

---