Multiphoton Ionization of Uracil at 355 nm

We present the experimental results from ionization and dissociation by multiphoton absorption (MPI) of uracil and a mixture of uracil with Ar using a Reflectron time of flight spectrometer along with radiation from 355 nm at pulsed Nd:YAG laser . We focus on the light ions production. The MPI mass spectra show that the presence and intensity of the resulting ions depend on the density power of the laser. The resulting ions in the mass spectra are identified and found similar behavior in the case of H+ and C+ as when multiple charged ions are used. Different results were found in contrast with those, recently reported, when electrons or photons of other wavelength were used. The number of 355nm absorbed photons was calculated accordingly to Keldysh theory and similar results were fond using pure uracil or uracil-Ar mixture. Our results are compared with those obtained in other laboratories under different experimental conditions, some of them show only partial agreement and differences are discussed.