Advanced

Role of stray light in the formation of high-resolution resonant photoelectron spectra: an experimental and theoretical study of N-2

Feifel, R; Baev, A; Gel'mukhanov, E; Agren, H; Andersson, M; Ohrwall, G; Piancastelli, MN; Miron, C; Ristinmaa Sörensen, Stacey LU and de Brito, AN, et al. (2004) In Journal of Electron Spectroscopy and Related Phenomena 134(1). p.49-65
Abstract
We show that the undular stray light, diffusely scattered by the optical system of a synchrotron beamline, can play an important role in the formation of high-resolution resonant photoelectron (RPE) spectra. The influence of the stray light is mediated through the Stokes doubling effect, with the Lorentzian tail of the spectral function being replaced by a more complicated form. This effect is shown to appear in the high-resolution resonant photoelectron spectrum of the N-2 molecule in which the spectral shape of the "non-Raman (NR) bands" differs qualitatively for the A(2)Pi(u) and X(2)Sigma(g)(+) final states. A particularly large enhancement of the non-Raman Stokes line is observed for the A-state while the picture is inverted for the... (More)
We show that the undular stray light, diffusely scattered by the optical system of a synchrotron beamline, can play an important role in the formation of high-resolution resonant photoelectron (RPE) spectra. The influence of the stray light is mediated through the Stokes doubling effect, with the Lorentzian tail of the spectral function being replaced by a more complicated form. This effect is shown to appear in the high-resolution resonant photoelectron spectrum of the N-2 molecule in which the spectral shape of the "non-Raman (NR) bands" differs qualitatively for the A(2)Pi(u) and X(2)Sigma(g)(+) final states. A particularly large enhancement of the non-Raman Stokes line is observed for the A-state while the picture is inverted for the X-state where the non-Raman band is suppressed. It is shown that the resonant photoemission profile is affected by two qualitatively different detunings, the detuning of the monochromatized line relative to the photoabsorption line and the detuning of the undulator harmonic relative to the same reference line. The experimental data show that the relative intensity of the non-Raman line strongly depends on the tuning of the undulator harmonic with respect to the selected monochromator bandpass, leading to a strong decrease of the Stokes line intensity for certain undulator detunings. A clear red-shift asymmetry for the decrease in the Stokes line intensity is observed when the monochromator line is detuned towards negative photon frequencies, whereas the picture is reverted for the situation of a positively detuned monochromator line. The results show the necessity to control the stray light and to investigate both the Raman and non-Raman contributions to the spectral profiles in order to avoid misinterpretation and in order to make full use of the information available in resonant photoemission spectra of molecules. (Less)
Please use this url to cite or link to this publication:
author
, et al. (More)
(Less)
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
high-resolution, spectral function, detuning
in
Journal of Electron Spectroscopy and Related Phenomena
volume
134
issue
1
pages
49 - 65
publisher
Elsevier
external identifiers
  • wos:000188230300005
  • scopus:0346332993
ISSN
0368-2048
DOI
10.1016/j.elspec.2003.09.007
language
English
LU publication?
yes
id
661681cb-3ede-436a-98d6-c08b51d83b88 (old id 289716)
date added to LUP
2007-10-22 14:04:15
date last changed
2017-08-13 04:19:51
@article{661681cb-3ede-436a-98d6-c08b51d83b88,
  abstract     = {We show that the undular stray light, diffusely scattered by the optical system of a synchrotron beamline, can play an important role in the formation of high-resolution resonant photoelectron (RPE) spectra. The influence of the stray light is mediated through the Stokes doubling effect, with the Lorentzian tail of the spectral function being replaced by a more complicated form. This effect is shown to appear in the high-resolution resonant photoelectron spectrum of the N-2 molecule in which the spectral shape of the "non-Raman (NR) bands" differs qualitatively for the A(2)Pi(u) and X(2)Sigma(g)(+) final states. A particularly large enhancement of the non-Raman Stokes line is observed for the A-state while the picture is inverted for the X-state where the non-Raman band is suppressed. It is shown that the resonant photoemission profile is affected by two qualitatively different detunings, the detuning of the monochromatized line relative to the photoabsorption line and the detuning of the undulator harmonic relative to the same reference line. The experimental data show that the relative intensity of the non-Raman line strongly depends on the tuning of the undulator harmonic with respect to the selected monochromator bandpass, leading to a strong decrease of the Stokes line intensity for certain undulator detunings. A clear red-shift asymmetry for the decrease in the Stokes line intensity is observed when the monochromator line is detuned towards negative photon frequencies, whereas the picture is reverted for the situation of a positively detuned monochromator line. The results show the necessity to control the stray light and to investigate both the Raman and non-Raman contributions to the spectral profiles in order to avoid misinterpretation and in order to make full use of the information available in resonant photoemission spectra of molecules.},
  author       = {Feifel, R and Baev, A and Gel'mukhanov, E and Agren, H and Andersson, M and Ohrwall, G and Piancastelli, MN and Miron, C and Ristinmaa Sörensen, Stacey and de Brito, AN and Bjorneholm, O and Karlsson, L and Svensson, S},
  issn         = {0368-2048},
  keyword      = {high-resolution,spectral function,detuning},
  language     = {eng},
  number       = {1},
  pages        = {49--65},
  publisher    = {Elsevier},
  series       = {Journal of Electron Spectroscopy and Related Phenomena},
  title        = {Role of stray light in the formation of high-resolution resonant photoelectron spectra: an experimental and theoretical study of N-2},
  url          = {http://dx.doi.org/10.1016/j.elspec.2003.09.007},
  volume       = {134},
  year         = {2004},
}