Multiple ionization of carbonaceous molecule clusters by intense 532 nm nanosecond laser

Using time-of-flight mass spectrometry, the multiple ionization process of seeded molecular cluster beams was studied by 532 nm nanosecond laser with intensity from 1010 to 1011 W·cm-2. Ions of Cq+, Oq+ and Iq+ (q=2~4) with translational energy of hundreds of eV were observed when the densest portion of the pulsed molecular beams of benzene, furan, methanol and methyl iodide were irradiated by the nanosecond laser. A model of “multiphoton ionization ignition-inverse bremsstrahlung absorption heated-electron collision ionization” is proposed to explain the generation of those multiply charged ions under the low intensity laser pulse. The kinds of the multiply charged ions as well as the ratio of each ion to the overall ion products did not decrease apparently even if the laser intensity