High-resolution multiphoton ionization and dissociation of H2 and D2 molecules in intense laser fields.

Abstract

We report on the multiphoton ionization and dissociation of hydrogen and deuterium molecules in intense (8\ifmmode\times\else\texttimes\fi{}${10}^{11--}$4\ifmmode\times\else\texttimes\fi{}${10}^{13}$ W/${\mathrm{cm}}^{2}$) laser fields. The investigations were performed with the second harmonics of two different laser systems, a 50-ps neodymium-doped yttrium lithium fluoride and a 10-ns neodymium-doped yttrium aluminum garnet laser. Measurements included energy-resolved photoelectron and mass spectroscopy. In addition, we report on a measurement of the dynamics of different above-threshold dissociation branching ratios for ${\mathrm{H}}_{2}^{+}$ and ${\mathrm{D}}_{2}^{+}$ over a wide range of laser intensities. Our results support the dressed-molecule picture at least qualitatively, but differences do exist with the quantitative predictions.