title: High-pressure transformation of SiO₂ glass from a tetrahedral to an octahedral network: a joint approach using neutron diffraction and molecular dynamics.
abstract: A combination of in situ high-pressure neutron diffraction at pressures up to 17.5(5) GPa and molecular dynamics simulations employing a many-body interatomic potential model is used to investigate the structure of cold-compressed silica glass. The simulations give a good account of the neutron diffraction results and of existing x-ray diffraction results at pressures up to ~60  GPa. On the basis of the molecular dynamics results, an atomistic model for densification is proposed in which rings are "zipped" by a pairing of five- and/or sixfold coordinated Si sites. The model gives an accurate description for the dependence of the mean primitive ring size ⟨n⟩ on the mean Si-O coordination number, thereby linking a parameter that is sensitive to ordering on multiple length scales to a readily measurable parameter that describes the local coordination environment.
authors.affiliation: Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom.
authors.forename: Anita
authors.initials: A
authors.lastname: Zeidler
authors.affiliation: Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom.
authors.forename: Kamil
authors.initials: K
authors.lastname: Wezka
authors.affiliation: Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom.
authors.forename: Ruth F
authors.initials: RF
authors.lastname: Rowlands
authors.affiliation: Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom.
authors.forename: Dean A J
authors.initials: DA
authors.lastname: Whittaker
authors.affiliation: Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom.
authors.forename: Philip S
authors.initials: PS
authors.lastname: Salmon
authors.affiliation: Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Polidori
authors.affiliation: Centre for Science at Extreme Conditions, School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom.
authors.forename: James W E
authors.initials: JW
authors.lastname: Drewitt
authors.affiliation: IMPMC, CNRS UMR 7590, Université Pierre et Marie Curie, 75252 Paris, France.
authors.forename: Stefan
authors.initials: S
authors.lastname: Klotz
authors.affiliation: Institut Laue Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble, France.
authors.forename: Henry E
authors.initials: HE
authors.lastname: Fischer
authors.affiliation: IMPS, Aberystwyth University, Aberystwyth SY23 3BZ, United Kingdom.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Wilding
authors.affiliation: ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom.
authors.forename: Craig L
authors.initials: CL
authors.lastname: Bull
authors.affiliation: ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom.
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Tucker
authors.affiliation: Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Mark
authors.initials: M
authors.lastname: Wilson