1
|
Heathcote D, Robertson PA, Butler AA, Ridley C, Lomas J, Buffett MM, Bell M, Vallance C. Electron-induced dissociation dynamics studied using covariance-map imaging. Faraday Discuss 2022; 238:682-699. [PMID: 35781475 DOI: 10.1039/d2fd00033d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Recently, covariance analysis has found significant use in the field of chemical reaction dynamics. When coupled with data from product time-of-flight mass spectrometry and/or multi-mass velocity-map imaging, it allows us to uncover correlations between two or more ions formed from the same parent molecule. While the approach has parallels with coincidence measurements, covariance analysis allows experiments to be performed at much higher count rates than traditional coincidence methods. We report results from electron-molecule crossed-beam experiments, in which covariance analysis is used to elucidate the dissociation dynamics of multiply-charged ions formed by electron ionisation over the energy range from 50 to 300 eV. The approach is able to isolate signal contributions from multiply charged ions even against a very large 'background' of signal arising from dissociation of singly-charged parent ions. Covariance between the product time-of-flight spectra identifies pairs of fragments arising from the same parent ions, while covariances between the velocity-map images ('recoil-frame covariances') reveal the relative velocity distributions of the ion pairs. We show that recoil-frame covariance analysis can be used to distinguish between multiple plausible dissociation mechanisms, including multi-step processes, and that the approach becomes particularly powerful when investigating the fragmentation dynamics of larger molecules with a higher number of possible fragmentation pathways.
Collapse
Affiliation(s)
- David Heathcote
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Patrick A Robertson
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Alexander A Butler
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Cian Ridley
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - James Lomas
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Madeline M Buffett
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Megan Bell
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Claire Vallance
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| |
Collapse
|
2
|
Bhatt P, Maiyelvaganan KR, Prakash M, Palaudoux J, Safvan CP, Hochlaf M. Fragmentation dynamics of CH 3Cl q+ ( q = 2,3): theory and experiment. Phys Chem Chem Phys 2022; 24:27619-27630. [DOI: 10.1039/d2cp02194c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We use advanced theoretical treatments and energetic ion collision induced fragmentation to investigate the unimolecular decomposition dynamics of CH3Clq+ (q = 2,3) ions, where both obvious bond breaking and bond rearrangement products are observed.
Collapse
Affiliation(s)
- Pragya Bhatt
- Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi – 110067, India
| | - K. R. Maiyelvaganan
- Department of Chemistry, Faculty of Engineering and Technology, SRM Institute of Science and Technology, SRM Nagar, Kattankulathur-603203, Chennai, TN, India
| | - M. Prakash
- Department of Chemistry, Faculty of Engineering and Technology, SRM Institute of Science and Technology, SRM Nagar, Kattankulathur-603203, Chennai, TN, India
| | - J. Palaudoux
- Sorbonne Université, CNRS, Laboratoire de Chimie Physique – Matière et Rayonnement, LCP-MR, F-75005, Paris, France
| | - C. P. Safvan
- Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi – 110067, India
| | - M. Hochlaf
- Université Gustave Eiffel, COSYS/IMSE, 5 Bd Descartes 77454, Champs sur Marne, France
| |
Collapse
|