Interaction of photons with molecules--cross-sections for photoabsorption, photoionization, and photodissociation.

A survey is given of recent progress in measurements of photoabsorption, photoionization, and photodissociation cross-sections of molecules in the wavelength range of photons in the vacuum ultraviolet (VUV), where the optical oscillator-strengths of most molecules are predominantly distributed. Some remarks are presented on molecules in the condensed phase. Particular emphasis is placed on the current understanding of spectroscopy and dissociation dynamics of molecules in the superexcited states which are produced through the interaction of photons in this wavelength range. In the VUV range, most of the observed super-excited states are assigned to high-Rydberg states which are vibrationally (and/or rotationally), doubly, or inner-core excited, and converge to each of the ion states.