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Ultrafast EUV probe for Molecular Reaction Dynamics

Final Report Summary - ULTRAFASTEUVPROBE (Ultrafast EUV probe for Molecular Reaction Dynamics)

During the lifetime of the project we developed and explored a new approach for time resolved Coulomb explosion imaging of molecular dynamics.
Ultrafast EUV pulses, produced using the emerging high-order harmonic generation (HHG) technique, allowed to induce Coulomb explosion (CE) following the absorption of a single EUV photon.
We constructed an experimental setup that allows disentangling these rare Coulomb explosion events from an overwhelming background of dissociative ionization. The 3D coincidence imaging of the Coulomb explosion products allowed to determine the kinetic energy released in different CE channels.
To achieve that goal, new 3D coincidence fragment imaging approaches were developed and tested on related experiments involving strong-field laser interaction with molecular anions reported in Kandhasamy et al (JPC A 2015), Shahi et al (JPCA 2017) and Shahi et al (RevSciInst 2018)
To verify that it is possible to relate the initial state of a neutral molecule to its different CE channels spectra, we performed detailed measurements of all the CE channels initiated by an HHG pulse from the methanol ground state. Multifaceted agreement with non-adiabatic AIMD simulations (specially developed for the project) confirmed that single EUV photon CE can remove the intrinsic ambiguity that plagued previous state of the art experimental approaches that were based on strong-field laser pulses. Luzon et al (PCCP 2018) and Luzon et al (JPC lett 2019)
We performed time resolved CE experiments that revealed rich and competing proton-transfer and electron-transfer dynamics in the Methanol dication ( Luzon et al , to be submitted 2019), thus resolving the conflicting evidence from previous strong-field experiments. Furthermore, we explored with time resolved Coulomb explosion the N-NO and NN-O bond cleavage dynamics in N2O.(Gope et al, submitted 2019)