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Shake-Up and Shake-Off Excitations and Associated Electron Losses in X-Ray Studies of Proteins

Persson, Petter LU ; Lunell, S.; Szöke, A.; Ziaja, B. and Hajdu, J. (2001) In Protein Science 10(12). p.2480-2484
Abstract
Photoionization of an atom by X-rays usually removes an inner shell electron from the atom, leaving behind a perturbed hollow ion whose relaxation may take different routes. In light elements, emission of an Auger electron is common. However, the energy and the total number of electrons released from the atom may be modulated by shake-up and shake-off effects. When the inner shell electron leaves, the outer shell electrons may find themselves in a state that is not an eigen-state of the atom in its surroundings. The resulting collective excitation is called shake-up. If this process also involves the release of low energy electrons from the outer shell, then the process is called shake-off. It is not clear how significant shake-up and... (More)
Photoionization of an atom by X-rays usually removes an inner shell electron from the atom, leaving behind a perturbed hollow ion whose relaxation may take different routes. In light elements, emission of an Auger electron is common. However, the energy and the total number of electrons released from the atom may be modulated by shake-up and shake-off effects. When the inner shell electron leaves, the outer shell electrons may find themselves in a state that is not an eigen-state of the atom in its surroundings. The resulting collective excitation is called shake-up. If this process also involves the release of low energy electrons from the outer shell, then the process is called shake-off. It is not clear how significant shake-up and shake-off contributions are to the overall ionization of biological materials like proteins. In particular, the interaction between the outgoing electron and the remaining system depends on the chemical environment of the atom, which can be studied by quantum chemical methods. Here we present calculations on model compounds to represent the most common chemical environments in proteins. The results show that the shake-up and shake-off processes affect 20% of all emissions from nitrogen, 30% from carbon, 40% from oxygen, and 23% from sulfur. Triple and higher ionizations are rare for carbon, nitrogen, and oxygen, but are frequent for sulfur. The findings are relevant to the design of biological experiments at emerging X-ray free-electron lasers. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Protein Science
volume
10
issue
12
pages
2480 - 2484
publisher
The Protein Society
external identifiers
  • scopus:0035176896
ISSN
1469-896X
DOI
10.1110/ps.ps.26201
language
English
LU publication?
no
id
86ce8ae2-7e06-4798-9eec-c80bddcbdd15 (old id 1457877)
date added to LUP
2009-08-27 16:45:09
date last changed
2018-05-29 11:24:16
@article{86ce8ae2-7e06-4798-9eec-c80bddcbdd15,
  abstract     = {Photoionization of an atom by X-rays usually removes an inner shell electron from the atom, leaving behind a perturbed hollow ion whose relaxation may take different routes. In light elements, emission of an Auger electron is common. However, the energy and the total number of electrons released from the atom may be modulated by shake-up and shake-off effects. When the inner shell electron leaves, the outer shell electrons may find themselves in a state that is not an eigen-state of the atom in its surroundings. The resulting collective excitation is called shake-up. If this process also involves the release of low energy electrons from the outer shell, then the process is called shake-off. It is not clear how significant shake-up and shake-off contributions are to the overall ionization of biological materials like proteins. In particular, the interaction between the outgoing electron and the remaining system depends on the chemical environment of the atom, which can be studied by quantum chemical methods. Here we present calculations on model compounds to represent the most common chemical environments in proteins. The results show that the shake-up and shake-off processes affect 20% of all emissions from nitrogen, 30% from carbon, 40% from oxygen, and 23% from sulfur. Triple and higher ionizations are rare for carbon, nitrogen, and oxygen, but are frequent for sulfur. The findings are relevant to the design of biological experiments at emerging X-ray free-electron lasers.},
  author       = {Persson, Petter and Lunell, S. and Szöke, A. and Ziaja, B. and Hajdu, J.},
  issn         = {1469-896X},
  language     = {eng},
  number       = {12},
  pages        = {2480--2484},
  publisher    = {The Protein Society},
  series       = {Protein Science},
  title        = {Shake-Up and Shake-Off Excitations and Associated Electron Losses in X-Ray Studies of Proteins},
  url          = {http://dx.doi.org/10.1110/ps.ps.26201},
  volume       = {10},
  year         = {2001},
}