Pyrazine Revisited

Pyrazine is shown by its Molecular Eigenstate Spectra and by its quantum beats to be a small molecule. The effect of Coriolis coupling and non-resonant light scattering are discussed. This paper further treats the so-called "fast component". Its existence with a decay time of about 100 psec has by now been firmly established. It finds its cause in the "bunching" of the molecular eigenstates in frequency space. For broad (i.e. psec) lasers it is therefore still useful to speak of pyrazine as an ILS-molecule. The characterization depends on the laser one uses in the experiment