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Nidin Vadassery

Publications and source records attributed to Nidin Vadassery.

2 recordsLinked to original sources

Rotational-state-controlled dissociative ionization dynamics in $\mathrm{CF_2I_2}$

We investigated strong-field dissociative ionization of $\mathrm{CF_2I_2}$ ensembles prepared in different initial rotational-state distributions using an electrostatic deflector. Pronounced changes in ion-channel branching ratios revealed a strong dependence of the fragmentation dynamics on the initial rotational excitation. Analysis of fragment yields and their laser-power dependences identifies resonance-enhanced multiphoton ionization through an intermediate excited state, $\mathrm{CF_2I_2^{\ast}}$. The measured branching behavior indicates competition between stabilization into bound ionic states and dissociative channels, driven by near-threshold non-adiabatic Coriolis-type coupling. Tuning the rotational energy by only a few $μ$eV is sufficient to significantly alter the ionization dynamics and to redistribute the reaction products. These findings demonstrate the key role of rotational excitation in controlling non-adiabatic dynamics following strong-field ionization of $\mathrm{CF_2I_2}$.

physics.chem-ph↗

Reaction Pathways of Water Dimer Following Single Ionization

Water dimer $(\text{H}_2\text{O})_2$ -- a vital component of the earth's atmosphere -- is an important prototypical hydrogen-bonded system. It provides direct insight into fundamental chemical and biochemical processes, e.g., proton transfer and ionic supramolecular dynamics occurring in astro- and atmospheric chemistry. Exploiting a purified molecular beam of water dimer and multi-mass ion imaging, we report the simultaneous detection of all generated ion products of $(\text{H}_2\text{O})^{+}_2$-fragmentation following single ionization. Detailed information about ion yields and reaction energetics of 13 ion-radical pathways, 6 of which are new, of $(\text{H}_2\text{O})^{+}_2$ are presented, including strong ${}^{18}\text{O}$-isotope effects.

physics.atm-clus↗