Coulomb explosion dynamics of methoxycarbonylsulfenyl chloride by 3D multimass imaging

Abstract

Coupling covariance map analysis with ultrafast laser-induced Coulomb explosion imaging (CEI) enabled us to characterise the dissociative ionisation dynamics of methoxycarbonylsulfenyl chloride (H₃COCOSCl). We applied a 3D multi-coincidence detection technique which is necessary for covariance imaging analysis. With the aid of such analysis, we found meaningful correlations between several product ion pairs that revealed different fragmentation channels. A weak, narrow correlation in the covariance image of H₃COC(O)⁺/Cl⁺ was assigned to a concerted three-body dissociation channel. We also observed a broadly distributed correlation in the covariance image of COS⁺/HCO⁺, which is ascribed to a multi-body fragmentation channel. Ab initio calculations were carried out to determine the likely starting structures. A very sharp feature in the covariance image of Cl⁺/ CH₃⁺ indicated that this pair of ions is produced from a two-body-like fragmentation event of CH₃Cl²⁺. We show by direct comparison with CEI of CH₃Cl that, contrary to a previously suggested assignment, this ion pair is produced from CH₃Cl, which is formed either in the bubbler or gas line before the molecular beam interacts with the laser beam.

GRAPHICAL ABSTRACT

KEYWORDS:

• Coulomb explosion imaging
• covariance imaging
• dissociation dynamics
• multi-coincidence detection technique
• ab initio calculations

Acknowledgments

The authors thank Prof. Wen Li for the valuable discussions. The authors also wish to thank Prof. Oleg Vasyutinskii for decades of friendship and fruitful collaboration.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data Availability

All data used in this paper is presented herein or available from the authors upon reasonable request.

Additional information

Funding

This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences of the U.S. Department of Energy under contract no. DE-SC0017130.