Multiple-photon absorption in cooled molecular beams of acenes compounds at 266 and 355 nm laser radiation

The cooled molecular beams of acenes compounds as naphthalene C₁₀H₈, anthracene C₁₄H₁₀, and ben- zantracene C₁₈H₁₂, were produced by adiabatic expansion in high vacuum chamber, 10^-8 torr. Molecular beams interacted with laser radiation of 266 and 355 nm, from a Ng:YAG laser at intensities up to 10¹⁰ W·cm^-2 At higher intensities the multiple photon absorption was possible. The number of photons was calculated using Keldysh approach. The dominant photophysics of photon-molecule interactions were photodissociation and photoionization processes depending on the wavelength used during the experiment. (paper)