Enhanced strong-field ionization and fragmentation of methanol using non-commensurate fields

TL;DR

This study demonstrates that using non-commensurate laser fields significantly enhances ionization and fragmentation of methanol, providing improved control over electron rescattering processes with potential applications in ultrafast chemistry.

Contribution

It introduces a novel experimental approach combining non-commensurate fields with intensity-difference spectra to enhance strong-field ionization of polyatomic molecules.

Findings

Orders of magnitude increase in product ions with non-commensurate fields

Mitigation of multi-photon ionization effects

Enhanced tunnel ionization and electron rescattering energy

Abstract

Electron-initiated chemistry with chemically relevant electron energies (10-200 eV) is at the heart of several high-energy processes and phenomena. To probe these dissociation and fragmentation reactions with femtosecond resolution requires the use of femtosecond lasers to induce ionization of the polyatomic molecules via electron rescattering. Here, we combine non-commensurate fields with intensity-difference spectra using methanol as a model system. Experimentally, we find orders of magnitude enhancement in several product ions of methanol when comparing coherent vs incoherent combinations of non-commensurate fields. This approach not only mitigates multi-photon ionization and multi-cycle effects during ionization but also enhances tunnel ionization and electron rescattering energy.