Energy Corrections to the Born–Oppenheimer Approximation. The Best Adiabatic Approximation

摘要: Procedures are presented for solving the previously derived exact coupled Schrodinger equations internal motion of a diatomic system, using both nonadiabatic variation methods and adiabatic perturbation methods. A “best adiabatic” (BA) approximation is variationally to give energetically best possible vibration–rotation energies potential‐energy curves. The BA electronic wavefunctions shown satisfy set equations, involving complete Hamiltonian which leads immediately generalization noncrossing rule Methods these obtain corrections Born–Oppenheimer approximation, valid in presence rotational degeneracies, presented. And finally, some upper‐and lower‐bound properties various approximations investigated.