Effect of slicing in velocity map imaging for the study of dissociation dynamics

TL;DR

This paper compares two slicing techniques in velocity map imaging to improve the accuracy of dissociation dynamics analysis of CO molecules, highlighting the advantages of wedge slicing over parallel slicing for low-energy ions.

Contribution

The study introduces a wedge slicing technique for velocity map imaging that provides a more accurate representation of dissociation dynamics compared to traditional parallel slicing.

Findings

Wedge slicing better captures low-energy ion dynamics.

Parallel slicing includes the entire Newton sphere, causing exaggeration.

Wedge slicing ensures equal contribution from all momentum spheres.

Abstract

Inelastic collision dynamics between isolated gas-phase carbon monoxide molecules and low energetic electrons (< 50 eV) has been studied using state-of-the-art velocity map imaging apparatus and reported previously. These were based on data analysis using the time-gated parallel slicing technique, which has recently revealed the drawback of lower momentum ion exaggeration mainly due to the inclusion of whole Newton sphere's of diameter $\le$ parallel slicing time window. To overcome this drawback, we report implementing a wedge slicing technique so that every momentum sphere contributes equally to the statistics. We also present a comparative study between these two techniques by reanalyzing the data using the time-gated parallel slicing technique. Unlike parallel slicing, the wedge slicing technique better represents the dissociation dynamics, particularly for the ions with low kinetic energy.