Coulomb explosion of methyl iodide clusters using giga watt laser pulses in the visible region: Effect of wavelength, polarisation and doping

Abstract

Nanosecond laser-induced Coulomb explosion studies have been carried out for methyl iodide clusters at 532 and 563 nm under similar laser intensity (∼ 5 × 109 W/cm2) conditions. Multiply charged atomic ions of carbon and iodine having large kinetic energy (∼ 100 s of eV) were observed in both the cases. Observation of higher charged states at 563 nm for Coulomb exploded atomic ions supports the preposition of enhanced inverse bremsstrahlung heating of the ionized cluster system at this wavelength. The angular distribution of the multiply charged atomic ions is found to be isotropic with respect to laser polarization direction at 532 nm. When water doped methyl iodide clusters were irradiated at 563 nm, highly charged atomic ions of oxygen along with carbon and iodine were also observed. This result suggests that the mechanism leading to Coulomb explosion is a collective property of the cluster as a whole and individual molecular properties do not play significant role. © Indian Academy of Sciences.