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Clusters provide an ideal microscopic medium for producing matter in an extremely excited state, upon interaction with laser. These clusters that are aggregates of atoms/molecules held together by weak van der Waals forces, when subjected to ultrashort intense laser pulses, get instantaneously energized to temperatures of up to thousands of Kelvin. Such excited state of matter possessing huge internal energy acts as a source of X-rays and also endures for adequate duration (subpicoseconds timescale) before exploding into energetic multiply charged atomic ions and electrons, under the influence of enormous Coulombic repulsive forces experienced by the highly ionized cluster constituents. The extent of kinetic energy gained by the cluster constituents can be realized from the fact that for deuterated clusters, collision between deuterons thrown off during the cluster explosion process triggers nuclear fusion, leading to generation of neutrons. This chapter provides glimpses of such studies, involving interaction of clusters with laser of varying wavelength and intensity, which is rich in physics and has potential technological applications.

Using the second harmonic output (532 nm) of a commercially available pulsed Nd:YAG laser interacting with pure and mixed clusters of iodo compounds, multiply charged ions of halogen group (F, Cl, Br and I) atoms have been generated based on the phenomenon of low intensity Coulomb explosion. This method provides a useful rugged tool for generation of multiply charged ions which can then be used for various applications. The effect of boiling point (vapour pressure) of the compound forming clusters has been correlated with the highest charged state of ion observed in time of flight mass spectrometer.