Relationship between x-ray emission and absorption spectroscopy and the local H-bond environment in water

The connection between specific spectrum features in the water X-ray absorption (XAS) and X-ray emission (XES) spectra and the local H-bond coordination is studied based on structures obtained from path-integral molecular dynamics simulations using either the opt-PBE-vdW density functional or the MB...

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Main Authors:	Zhovtobriukh, Iurii, Besley, Nicholas A., Fransson, Thomas, Nilsson, Anders, Pettersson, Lars G.M.
Format:	Article
Language:	English
Published:	American Institute of Physics 2018
Online Access:	http://eprints.nottingham.ac.uk/50560/ http://eprints.nottingham.ac.uk/50560/ http://eprints.nottingham.ac.uk/50560/ http://eprints.nottingham.ac.uk/50560/1/final-submitted.pdf

id	nottingham-50560
recordtype	eprints
spelling	nottingham-505602018-06-26T12:44:07Z http://eprints.nottingham.ac.uk/50560/ Relationship between x-ray emission and absorption spectroscopy and the local H-bond environment in water Zhovtobriukh, Iurii Besley, Nicholas A. Fransson, Thomas Nilsson, Anders Pettersson, Lars G.M. The connection between specific spectrum features in the water X-ray absorption (XAS) and X-ray emission (XES) spectra and the local H-bond coordination is studied based on structures obtained from path-integral molecular dynamics simulations using either the opt-PBE-vdW density functional or the MB-pol force field. Computing the XES spectrum using all molecules in a snapshot results in only one peak in the lone-pair (1b1) region while the experiment shows two peaks separated by 0.8-0.9 eV. Different H-bond configurations were classified based on the local structure index (LSI) and a geometrical H-bond cone criterion. We find that tetrahedrally coordinated molecules characterised by high LSI values and two strong donated and two strong accepted H-bonds contribute to the low energy 1b1 emission peak and to the post-edge region in absorption. Molecules with asymmetric H-bond environment with one strong accepted and one strong donated H-bond and low LSI values give rise to the high energy 1b1 peak in the emission spectrum and mainly contribute to the pre-edge and main-edge in the absorption spectrum. The 1b1 peak splitting can be increased to 0.62 eV by imposing constraints on the H-bond length, i.e. for very tetrahedral structures short H-bonds (less than 2.68 Å) and for very asymmetric structures elongated H-bonds (longer than 2.8 Å). Such structures are present, but underrepresented, in the simulations which give more of an average of the two extremes. American Institute of Physics 2018-04-10 Article PeerReviewed application/pdf en http://eprints.nottingham.ac.uk/50560/1/final-submitted.pdf Zhovtobriukh, Iurii and Besley, Nicholas A. and Fransson, Thomas and Nilsson, Anders and Pettersson, Lars G.M. (2018) Relationship between x-ray emission and absorption spectroscopy and the local H-bond environment in water. Journal of Chemical Physics, 148 (14). 144507/1-144507/. ISSN 1089-7690 https://aip.scitation.org/doi/full/10.1063/1.5009457 doi:10.1063/1.5009457 doi:10.1063/1.5009457
repository_type	Digital Repository
institution_category	Local University
institution	University of Nottingham Malaysia Campus
building	Nottingham Research Data Repository
collection	Online Access
language	English
description	The connection between specific spectrum features in the water X-ray absorption (XAS) and X-ray emission (XES) spectra and the local H-bond coordination is studied based on structures obtained from path-integral molecular dynamics simulations using either the opt-PBE-vdW density functional or the MB-pol force field. Computing the XES spectrum using all molecules in a snapshot results in only one peak in the lone-pair (1b1) region while the experiment shows two peaks separated by 0.8-0.9 eV. Different H-bond configurations were classified based on the local structure index (LSI) and a geometrical H-bond cone criterion. We find that tetrahedrally coordinated molecules characterised by high LSI values and two strong donated and two strong accepted H-bonds contribute to the low energy 1b1 emission peak and to the post-edge region in absorption. Molecules with asymmetric H-bond environment with one strong accepted and one strong donated H-bond and low LSI values give rise to the high energy 1b1 peak in the emission spectrum and mainly contribute to the pre-edge and main-edge in the absorption spectrum. The 1b1 peak splitting can be increased to 0.62 eV by imposing constraints on the H-bond length, i.e. for very tetrahedral structures short H-bonds (less than 2.68 Å) and for very asymmetric structures elongated H-bonds (longer than 2.8 Å). Such structures are present, but underrepresented, in the simulations which give more of an average of the two extremes.
format	Article
author	Zhovtobriukh, Iurii Besley, Nicholas A. Fransson, Thomas Nilsson, Anders Pettersson, Lars G.M.
spellingShingle	Zhovtobriukh, Iurii Besley, Nicholas A. Fransson, Thomas Nilsson, Anders Pettersson, Lars G.M. Relationship between x-ray emission and absorption spectroscopy and the local H-bond environment in water
author_facet	Zhovtobriukh, Iurii Besley, Nicholas A. Fransson, Thomas Nilsson, Anders Pettersson, Lars G.M.
author_sort	Zhovtobriukh, Iurii
title	Relationship between x-ray emission and absorption spectroscopy and the local H-bond environment in water
title_short	Relationship between x-ray emission and absorption spectroscopy and the local H-bond environment in water
title_full	Relationship between x-ray emission and absorption spectroscopy and the local H-bond environment in water
title_fullStr	Relationship between x-ray emission and absorption spectroscopy and the local H-bond environment in water
title_full_unstemmed	Relationship between x-ray emission and absorption spectroscopy and the local H-bond environment in water
title_sort	relationship between x-ray emission and absorption spectroscopy and the local h-bond environment in water
publisher	American Institute of Physics
publishDate	2018
url	http://eprints.nottingham.ac.uk/50560/ http://eprints.nottingham.ac.uk/50560/ http://eprints.nottingham.ac.uk/50560/ http://eprints.nottingham.ac.uk/50560/1/final-submitted.pdf
first_indexed	2018-09-06T14:14:30Z
last_indexed	2018-09-06T14:14:30Z
_version_	1610867823527067648

Relationship between x-ray emission and absorption spectroscopy and the local H-bond environment in water

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