Velocity map imaging with non-uniform detection: quantitative molecular axis alignment measurements via Coulomb explosion imaging

TL;DR

This paper introduces a novel inversion method for velocity map images that accounts for non-uniform detection functions, enabling accurate, quantitative measurements of molecular axis alignment from Coulomb explosion imaging.

Contribution

It develops a new inversion technique that incorporates detection biases, allowing for precise molecular alignment measurements even with asymmetric detection.

Findings

Successfully removes angular bias in Coulomb explosion images

Enables quantitative measurement of molecular axis alignment

Improves accuracy over standard inversion methods

Abstract

We present a method for inverting charged particle velocity map images which incoorporates a non-uniform detection function. This method is applied to the specific case of extracting molecular axis alignment from Coulomb explosion imaging probes in which the probe itself has a dependence on molecular orientation which often removes cylindrical symmetry from the experiment and prevents the use of standard inversion techniques for the recovery of the molecular axis distribution. By incorporating the known detection function, it is possible to remove the angular bias of the Coulomb explosion probe process and invert the image to allow quantitative measurement of the degree of molecular axis alignment.