Tracing photoionisation behaviour of methyl iodide in gas phase: From isolated molecule to molecular aggregate

Publication date: December 2017 Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Volume 33 Author(s): Soumitra Das, Pramod Sharma, Rajesh K. Vatsa Methyl iodide (CH3I) is one of the most studied molecule in the field of photochemistry. This molecule has been investigated by a variety of light sources including lamps, different lasers as well as synchrotron radiation of varying intensity and wavelength. In this review, photoionisation studies of CH3I have been summarised for monomer (CH3I) and its aggregates i.e., cluster (CH3I)n which were excited with a range of photon energy and intensity using different sources. For the case of monomer, ionisation process follows either ionisation followed by dissociation (ladder climbing mechanism) or dissociation followed by ionisation (ladder switching mechanism) depending upon the wavelength and intensity of ionisation source. In case of CH3I ionisation by synchrotron radiation, singly and doubly charged molecular ions were observed depending upon the energy of photon. For ionisation using laser sources, singly and multiply charged ions were observed for laser pulses ranging from femtosecond to nanosecond duration. For the case of cluster (CH3I)n ionisation with laser sources, multiply charged ions were observed leading to Coulomb explosion phenomena. Lowest possible laser intensity observed to induce Coulomb explosion in CH3I clusters was ∼109 W/cm2 using nanosecond laser pulses. Since observation of...
Source: Journal of Photochemistry and Photobiology C: Photochemistry Reviews - Category: Chemistry Source Type: research