Diverges, and oscillates if both these series converge.
If, on the other hand M is small compared with in, u is nearly equal to unity, and the root1 of (12) are a2=g/(a+b) and fri_-=nigIM.(a~b)/ab, approximately The former root makes 0=4,, nearly; in the corresponding normal mode m oscillates like the bob of a simple pendulum of length a+b.
At a certain temperature a stage will be reached in which it is a frequent occurrence for a molecule to wander so far from its position of equilibrium, that it does not return but falls into a new position of equilibrium and oscillates about this.
How would you define oscillates? Add your definition here.