Nonlinear optics in space

A detailed model for nonlinear photoexcitation of H2 in space is proposed and considered at length. It is shown that, on the basis of this model, one is able to provide at least partial explanations for three famous astrophysical spectral mysteries pertaining to our galaxy. These concern the carrier identities of the Diffuse Interstellar (Absorption) Bands (DIBs), the Unidentified Infrared (Emission) Bands (UIBs), and the visible bands emitted by the Red Rectangle nebula.