# Time-resolved multi-mass ion imaging: femtosecond UV-VUV pump-probe spectroscopy with the PImMS camera

## TL;DR

This paper introduces a novel time-resolved multi-mass ion imaging technique combining PImMS camera with femtosecond UV-VUV pump-probe spectroscopy, enabling detailed studies of molecular dynamics with high temporal and mass resolution.

## Contribution

It presents the integration of PImMS camera with ultrafast pump-probe spectroscopy for high-resolution, time-resolved multi-mass ion imaging, expanding capabilities for studying excited state molecular dynamics.

## Key findings

- Successful demonstration with C$_2$F$_3$I photolysis
- Observation of complex wavepacket dynamics
- Enhanced detection of photofragments across multiple masses

## Abstract

The Pixel-Imaging Mass Spectrometry (PImMS) camera allows for 3D charged particle imaging measurements, in which the particle time-of-flight is recorded along with $(x,y)$ position. Coupling the PImMS camera to an ultrafast pump-probe velocity-map imaging spectroscopy apparatus therefore provides a route to time-resolved multi-mass ion imaging, with both high count rates and large dynamic range, thus allowing for rapid measurements of complex photofragmentation dynamics. Furthermore, the use of vacuum ultraviolet wavelengths for the probe pulse allows for an enhanced observation window for the study of excited state molecular dynamics in small polyatomic molecules having relatively high ionization potentials. Herein, preliminary time-resolved multi-mass imaging results from C$_2$F$_3$I photolysis are presented. The experiments utilized femtosecond UV and VUV (160.8~nm and 267~nm) pump and probe laser pulses in order to demonstrate and explore this new time-resolved experimental ion imaging configuration. The data indicates the depth and power of this measurement modality, with a range of photofragments readily observed, and many indications of complex underlying wavepacket dynamics on the excited state(s) prepared.