Kinetic Energy-Broadened Spatial Map Imaging for Recovering Dynamical Information

The highly successful velocity map imaging (VMI) technique plays a central role in revealing light-matter interactions. Here we demonstrate the related but distinct kinetic energy-broadened spatial map imaging (KESMI) option for recovering KE and angular recoil information on photophysical processes using a VMI system operating in different out-of-focus modes. The characteristic single or double stripes and related steps in the vertical intensity profiles of KESMIs of photoelectrons (PEs) from Ar ionization allow breakthrough developments of a potent global model that enables an understanding and analysis of these patterns. These signatures reflect the relationship between the observed features and predicted convolved discrete KEs and angular distributions. The derivation of the velocity distribution of the PEs ensuing from the ionization of a single H₂O quantum state based on the measured and simulated KESMI provides another rigorous test demonstrating and realizing the feasibility of this new approach, which holds future promise on its own or combined with VMI.