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Title: N-K near-edge x-ray-absorption fine structures of acetonitrile in gas phase

Abstract

The dynamic processes of N(1s) core-hole excitation in gas-phase CH{sub 3}CN molecule have been studied at both Hartree-Fock and hybrid density-functional theory levels. The vibrational structure is analyzed for fully optimized core-excited states. Frank-Condon factors are obtained using the linear coupling model for various potential surfaces. It is found that the vibrational profile of the N-K absorption can be largely described by a summation of two vibrational progressions: a structure-rich profile of {nu}{sub (CN)} stretching mode and a large envelope of congestioned vibrational levels related to the strong (-C-CN) terminal bending bond. Excellent agreement between theoretical and experimental spectra is obtained.

Authors:
; ; ; ;  [1];  [2];  [3]
  1. Laboratoire de Chimie Physique, Matiere et Rayonnement, Unite Mixte de Recherche (UMR) 7614, Universite Pierre et Marie Curie, 11, rue Pierre et Marie Curie, 75231 Paris, Cedex 05 (France)
  2. (Finland)
  3. (Sweden)
Publication Date:
OSTI Identifier:
20723264
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 123; Journal Issue: 21; Other Information: DOI: 10.1063/1.2104327; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTROSCOPY; ACETONITRILE; COUPLING; DENSITY FUNCTIONAL METHOD; EXCITATION; FINE STRUCTURE; HARTREE-FOCK METHOD; K ABSORPTION; MOLECULAR STRUCTURE; VIBRATIONAL STATES; X RADIATION; X-RAY SPECTROSCOPY

Citation Formats

Carniato, Stephane, Taieeb, Richard, Kukk, Edwin, Luo, Yi, Brena, Barbara, Department of Physical Sciences, University of Oulu, P.O. Box 3000, FIN-90014 Oulu, and Theoretical Chemistry, Royal Institute of Technology, AlbaNova, S-106 91 Stockholm. N-K near-edge x-ray-absorption fine structures of acetonitrile in gas phase. United States: N. p., 2005. Web. doi:10.1063/1.2104327.
Carniato, Stephane, Taieeb, Richard, Kukk, Edwin, Luo, Yi, Brena, Barbara, Department of Physical Sciences, University of Oulu, P.O. Box 3000, FIN-90014 Oulu, & Theoretical Chemistry, Royal Institute of Technology, AlbaNova, S-106 91 Stockholm. N-K near-edge x-ray-absorption fine structures of acetonitrile in gas phase. United States. doi:10.1063/1.2104327.
Carniato, Stephane, Taieeb, Richard, Kukk, Edwin, Luo, Yi, Brena, Barbara, Department of Physical Sciences, University of Oulu, P.O. Box 3000, FIN-90014 Oulu, and Theoretical Chemistry, Royal Institute of Technology, AlbaNova, S-106 91 Stockholm. Thu . "N-K near-edge x-ray-absorption fine structures of acetonitrile in gas phase". United States. doi:10.1063/1.2104327.
@article{osti_20723264,
title = {N-K near-edge x-ray-absorption fine structures of acetonitrile in gas phase},
author = {Carniato, Stephane and Taieeb, Richard and Kukk, Edwin and Luo, Yi and Brena, Barbara and Department of Physical Sciences, University of Oulu, P.O. Box 3000, FIN-90014 Oulu and Theoretical Chemistry, Royal Institute of Technology, AlbaNova, S-106 91 Stockholm},
abstractNote = {The dynamic processes of N(1s) core-hole excitation in gas-phase CH{sub 3}CN molecule have been studied at both Hartree-Fock and hybrid density-functional theory levels. The vibrational structure is analyzed for fully optimized core-excited states. Frank-Condon factors are obtained using the linear coupling model for various potential surfaces. It is found that the vibrational profile of the N-K absorption can be largely described by a summation of two vibrational progressions: a structure-rich profile of {nu}{sub (CN)} stretching mode and a large envelope of congestioned vibrational levels related to the strong (-C-CN) terminal bending bond. Excellent agreement between theoretical and experimental spectra is obtained.},
doi = {10.1063/1.2104327},
journal = {Journal of Chemical Physics},
number = 21,
volume = 123,
place = {United States},
year = {Thu Dec 01 00:00:00 EST 2005},
month = {Thu Dec 01 00:00:00 EST 2005}
}
  • Near edge x-ray absorption fine structure spectra have been measured and interpreted by means of density functional theory for five different azabenzenes (pyridine, pyridazine, pyrimidine, pyrazine, and s-triazine) in the gas phase. The experimental and theoretical spectra at the N 1s and C 1s edges show a strong resonance assigned to the transition of the 1s electron in the respective N or C atoms to the lowest unoccupied molecular orbital with {pi}* symmetry. As opposed to the N 1s edge, at the C 1s edge this resonance is split due to the different environments of the core hole atom inmore » the molecule. The shift in atomic core-level energy due to a specific chemical environment is explained with the higher electronegativity of the N atom compared to the C atom. The remaining resonances below the ionization potential (IP) are associated to {sigma} or {pi} orbitals with mixed valence/Rydberg character. Upon N addition, a reduction of intensity is observed in the Rydberg region at both edges as compared to the intensity in the continuum. Above the IP one or more resonances are seen and ascribed here to transitions to {sigma}* orbitals. Calculating the experimental and theoretical {delta}{sub {pi}} term values at both edges, we observe that they are almost the same within {+-}1 eV as expected for isoelectronic bonded pairs. The term values of the {pi}* and {sigma}* resonances are discussed in terms of the total Z number of the atoms participating in the bond.« less
  • No abstract prepared.
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  • The inner shell excitation of pyrimidine and some halogenated pyrimidines near the C and N K-edges has been investigated experimentally by near edge x-ray absorption fine structure spectroscopy and theoretically by density functional theory calculations. The selected targets, 5-Br-pyrimidine, 2-Br-pyrimidine, 2-Cl-pyrimidine, and 5-Br-2-Cl-pyrimidine, allow the effects of the functionalization of the pyrimidine ring to be studied either as a function of different halogen atoms bound to the same molecular site or as a function of the same halogen atom bound to different molecular sites. The results show that the individual characteristics of the different spectra of the substituted pyrimidines canmore » be rationalized in terms of variations in electronic and geometrical structures of the molecule depending on the localization and the electronegativity of the substituent.« less
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