Separating processes in molecular photoionization studies: Mining coincidence momentum imaging data

Speaker: Eric Wells, Augustana University

Program Description
Strong-field photoionization of polyatomic molecules typically imparts significant excess energy to a molecule, stimulating numerous internal dynamics leading to fragmentation.  Even when momentum imaging experiments (e.g. COLTRIMS) obtain coincidence data that is ideal for reconstructing individual molecular processes, the features of many relatively rare processes remain elusive, buried under an avalanche of competition.  This talk explores two analysis methods for disentangling the data and some resulting insights.  The first method is use of the Jacobi coordinates’ conjugate momenta to reduce the dimensionality of multi-body fragmentation [1].  The second method extends deuterium tagging to distinguish the three hydrogen sites of ethanol [2].  These examples illustrate that the collective weight of small processes can exceed the contribution from the dominant process in strong-field molecular photoionization. 

*Supported by National Science Foundation grant number PHY-2309192.
1.  J. Rajput et al., Phys. Rev. Lett. 120, 103001 (2018).
2. T. Severt et al., Nature Communications 15, 74 (2024).