University of Oulu

Kivimäki, A., Stråhlman, C., Richter, R., Sankari, R. (2018) Fragmentation of Methanol Molecules after Core Excitation and Core Ionization Studied by Negative-Ion/Positive-Ion Coincidence Experiments. Journal of Physical Chemistry A, 122 (1), 224-233. doi:10.1021/acs.jpca.7b11250

Fragmentation of methanol molecules after core excitation and core ionization studied by negative-ion/positive-ion coincidence experiments

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Author: Kivimäki, Antti1,2; Stråhlman, Christian3,2; Richter, Robert4;
Organizations: 1Nano and Molecular Systems Research Unit, University of Oulu, P.O. Box 3000, 90014 Oulu, Finland
2MAX IV Laboratory, Lund University, P.O. Box 118, 22100 Lund, Sweden
3Malmö University, 20506 Malmö, Sweden
4Elettra-Sincrotrone Trieste, Area Science Park, 34149 Trieste, Italy
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 1.6 MB)
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Language: English
Published: American Chemical Society, 2018
Publish Date: 2018-12-13


We have studied the fragmentation of the methanol molecule after core excitation and core ionization by observing coincidences between negative and positive ions. Five different negative ions (H, C, CH, O, and OH) were observed at both the C 1s and O 1s edges. As negative ion formation occurs after resonant and normal Auger decay of core–hole states, it is necessarily linked with the release of positively charged fragments. Our data show that such fragmentation can happen in many different ways: We found approximately 30 negative-ion/positive-ion/positive-ion coincidence (NIPIPICO) channels. All involve only singly charged positive ions. Fragmentation channels leading to atomic ions are the most probable, but positive molecular ions are also frequently found in the context of anion formation. Coincidence yields as a function of photon energy were determined for the most intense NIPIPICO channels. Adding together the data measured at different photon energies, we could also verify the occurrence of four-ion coincidences, which involved one negative ion (H or O) and three positive ions.

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Series: The journal of physical chemistry. A
ISSN: 1089-5639
ISSN-E: 1520-5215
ISSN-L: 1089-5639
Volume: 122
Issue: 1
Pages: 224 - 233
DOI: 10.1021/acs.jpca.7b11250
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
Copyright information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry A, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see