Temperature of neutral clusters produced in a seeded molecular beam, and energy transfer during the photoionization process Original Research Article

Sodium clusters produced in a seeded molecular beam are ionized by a low laser fluence just above their ionization potential. Evaporative rates of cluster ions are measured as a function of the ionization laser energy. These rates evolve strongly near the ionization threshold of the clusters. The temperature of the neutral clusters has been deduced from the evaporative rates. This temperature is in good agreement with the temperature expected in an evaporative ensemble for the neutral clusters. As the energy of the laser increases, a transfer of energy, from the photon to the vibrational internal modes of the cluster, is observed during the photoionization.