Wavelength-Dependent Photodissociation of Iodomethylbutane

TL;DR

This study investigates how different wavelengths of optical lasers influence the photodissociation patterns of a chiral molecule, using ultrafast XUV pulses and ion imaging to reveal wavelength-dependent fragmentation dynamics.

Contribution

It demonstrates the wavelength-dependent dissociation behavior of 1-iodo-2-methyl-butane under ultrafast XUV irradiation, highlighting the importance of laser parameters in controlling molecular fragmentation.

Findings

800 nm laser causes slower dissociation than 267 nm

Fragment yields vary significantly with wavelength and intensity

Ion spectra differ notably between pump wavelengths

Abstract

Ultrashort XUV pulses of the Free-Electron-LASer in Hamburg (FLASH) were used to investigate laser-induced fragmentation patterns of the prototypical chiral molecule 1-iodo-2-methyl-butane (C$_5$H$_{11}$I) in a pump-probe scheme. Ion velocity-map images and mass spectra of optical-laser-induced fragmentation were obtained for subsequent FEL exposure with photon energies of 63 eV and 75 eV. These energies specifically address the iodine 4d edge of neutral and singly charged iodine, respectively. The presented ion spectra for two optical pump-laser wavelengths, i.e., 800 nm and 267 nm, reveal substantially different cationic fragment yields in dependence on the wavelength and intensity. For the case of 800-nm-initiated fragmentation, the molecule dissociates notably slower than for the 267-nm pump. The results underscore the importance of considering optical-laser wavelength and intensity in the dissociation dynamics of this prototypical chiral molecule that is a promising candidate for future studies of its asymmetric nature.