Evidence for charge-induced dipole reaction in laser ionized van der Waals clusters: a case of Fe²⁺ reacting with argon atoms inside a cluster

Abstract

Fe(CO) 5 -doped argon clusters have been photo-ionized by 532 nm, nanosecond laser pulses and the ions generated as a result of laser-cluster interaction were detected using time-of-flight mass spectrometry.Formation of [FeAr] + was observed to coincide with generation of Fe 2+ . Reaction of singly charged iron ion (Fe + ) with argon did not give rise to a detectable amount of [FeAr] + . However, for the Fe 2+ case, the yield of [FeAr] + is found to depend on the laser intensity and size of the argon cluster. Density functional theory calculations suggest that the reaction of Fe 2+ with Ar dimer is energetically 4 times more favorable for generation of [FeAr] + as compared to the reaction of Fe + with Ar. Based on the intensity of different ions, two orders of magnitude enhancement in the rate constant has been estimated for the reaction of iron ion towards argon with a change of ionic state from singly charged to doubly charged. The present experimental and theoretical studies demonstrate the existence of an additional and efficient intra-cluster reaction channel based on charge-induced dipole reaction for generation of [FeAr] + from the photo-ionization of Fe(CO) 5 -doped argon clusters.

Mass spectrometric and charge density studies of organometallic clusters photoionized by gigawatt laser pulses

“…Hence, further studies were directed to explore the ionization processes and establish the mechanism by which clusters exhibits multiple ionization and subsequent Coulomb explosion under such low intensity laser fields. For this purpose, experiments were performed on pure (Badani et al, 2011(Badani et al, , 2014aDas et al, 2011aDas et al, ,b, 2012 as well as doped cluster systems (Badani et al, , 2013(Badani et al, , 2014a. Here in, homogenous clusters comprising of single component are referred as pure clusters.…”