Task: Text Categorization
Input (English): For the d-mode approximation associated with this effect, the Racah and Lanczos methods can be effectively applied. It is typically characterized by a parameter that is equal to 1 over h-bar omega times the energy difference between the central maxima and the distorted minima, and for substituted benzenoid cations that parameter is not usually greater than 1. The result of this effect can appear as a vertical line on a Tanabe-Sugano diagram. Where bending results in a lowering of symmetry for linear molecules, there exists a related effect named after one of this effect's namesakes and Renner. A consequence of this effect is the mixing of electronic and nuclear motions, also known as vibronic coupling, which can result in the breakdown in Born-Oppenheimer approximation. Coming in pseudo and dynamical versions, for 10 points, name this doubly-eponymous effect, which is an instability of nonlinear molecular systems in orbitally degenerate electronic states
Output (English): Science