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Fragmentation of Methanol Molecules after Core Excitation and Core Ionization Studied by Negative-Ion/Positive-Ion Coincidence Experiments

Kivimäki, Antti LU ; Stråhlman, Christian LU ; Richter, Robert and Sankari, Rami LU (2018) In Journal of Physical Chemistry A 122(1). p.224-233
Abstract

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... (More)

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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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Physical Chemistry A
volume
122
issue
1
pages
10 pages
publisher
The American Chemical Society
external identifiers
  • scopus:85040528642
ISSN
1089-5639
DOI
10.1021/acs.jpca.7b11250
language
English
LU publication?
yes
id
4275e4d5-b8d5-4546-bb49-5962764819bd
date added to LUP
2018-01-30 12:05:37
date last changed
2018-01-31 03:00:09
@article{4275e4d5-b8d5-4546-bb49-5962764819bd,
  abstract     = {<p>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<sup>-</sup>, C<sup>-</sup>, CH<sup>-</sup>, O<sup>-</sup>, and OH<sup>-</sup>) 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<sup>-</sup> or O<sup>-</sup>) and three positive ions.</p>},
  author       = {Kivimäki, Antti and Stråhlman, Christian and Richter, Robert and Sankari, Rami},
  issn         = {1089-5639},
  language     = {eng},
  month        = {01},
  number       = {1},
  pages        = {224--233},
  publisher    = {The American Chemical Society},
  series       = {Journal of Physical Chemistry A},
  title        = {Fragmentation of Methanol Molecules after Core Excitation and Core Ionization Studied by Negative-Ion/Positive-Ion Coincidence Experiments},
  url          = {http://dx.doi.org/10.1021/acs.jpca.7b11250},
  volume       = {122},
  year         = {2018},
}