will split into two close-lying nondegenerate states for non-linear configurations. As part of the Renner–Teller effect, the rovibronic levels of such a pair of states will be strongly Coriolis coupled by the rotational kinetic energy operator causing a breakdown of the Born-Oppenheimer approximation.
will divide into two adjacent non-degenerate states for nonlinear configurations. As part of the Renner–Teller effect, the rovibronic levels of such a pair of states will be strongly Coriolis coupled by the rotational kinetic energy operator causing a disruption of the Born-Oppenheimer approximation.