Structural changes in amorphous solid water films on heating to 120-140 K and 150-160 K seen by positronium annihilation spectroscopy

S. Townrow, P. G. Coleman

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Changes in the structure of amorphous solid water films, grown by vapour deposition on a copper substrate at 75 K and then held at 120 K for 10 min to effect pore collapse, have been observed in the ranges 122-139 K and 150-162 K using positronium annihilation spectroscopy. It is proposed that the former is associated with the glass transition, with an effective activation energy of 0.266(3) eV. The data for the latter, which exhibit minima suggesting the temporary introduction of molecular disorder, can be processed to yield an effective activation energy of 0.47(2) eV, and are consistent with either a structural reorganization of the crystalline lattice or a relaxation of the amorphous structure mediated by defect migration.

Original languageEnglish
Article number225401
JournalJournal of Physics: Condensed Matter
Volume27
Issue number22
DOIs
Publication statusPublished - 10 Jun 2015

Fingerprint

positronium
Activation energy
Spectroscopy
activation energy
Heating
Vapor deposition
heating
Water
Crystal lattices
water
spectroscopy
Copper
Glass transition
vapor deposition
disorders
Crystalline materials
porosity
copper
Defects
glass

Keywords

  • positronium
  • structure
  • water ice

Cite this

@article{138f7c65b146488192c9d3333ed68400,
title = "Structural changes in amorphous solid water films on heating to 120-140 K and 150-160 K seen by positronium annihilation spectroscopy",
abstract = "Changes in the structure of amorphous solid water films, grown by vapour deposition on a copper substrate at 75 K and then held at 120 K for 10 min to effect pore collapse, have been observed in the ranges 122-139 K and 150-162 K using positronium annihilation spectroscopy. It is proposed that the former is associated with the glass transition, with an effective activation energy of 0.266(3) eV. The data for the latter, which exhibit minima suggesting the temporary introduction of molecular disorder, can be processed to yield an effective activation energy of 0.47(2) eV, and are consistent with either a structural reorganization of the crystalline lattice or a relaxation of the amorphous structure mediated by defect migration.",
keywords = "positronium, structure, water ice",
author = "S. Townrow and Coleman, {P. G.}",
year = "2015",
month = "6",
day = "10",
doi = "10.1088/0953-8984/27/22/225401",
language = "English",
volume = "27",
journal = "Journal of Physics: Condensed Matter",
issn = "0953-8984",
publisher = "IOP Publishing",
number = "22",

}

TY - JOUR

T1 - Structural changes in amorphous solid water films on heating to 120-140 K and 150-160 K seen by positronium annihilation spectroscopy

AU - Townrow, S.

AU - Coleman, P. G.

PY - 2015/6/10

Y1 - 2015/6/10

N2 - Changes in the structure of amorphous solid water films, grown by vapour deposition on a copper substrate at 75 K and then held at 120 K for 10 min to effect pore collapse, have been observed in the ranges 122-139 K and 150-162 K using positronium annihilation spectroscopy. It is proposed that the former is associated with the glass transition, with an effective activation energy of 0.266(3) eV. The data for the latter, which exhibit minima suggesting the temporary introduction of molecular disorder, can be processed to yield an effective activation energy of 0.47(2) eV, and are consistent with either a structural reorganization of the crystalline lattice or a relaxation of the amorphous structure mediated by defect migration.

AB - Changes in the structure of amorphous solid water films, grown by vapour deposition on a copper substrate at 75 K and then held at 120 K for 10 min to effect pore collapse, have been observed in the ranges 122-139 K and 150-162 K using positronium annihilation spectroscopy. It is proposed that the former is associated with the glass transition, with an effective activation energy of 0.266(3) eV. The data for the latter, which exhibit minima suggesting the temporary introduction of molecular disorder, can be processed to yield an effective activation energy of 0.47(2) eV, and are consistent with either a structural reorganization of the crystalline lattice or a relaxation of the amorphous structure mediated by defect migration.

KW - positronium

KW - structure

KW - water ice

UR - http://www.scopus.com/inward/record.url?scp=84930226138&partnerID=8YFLogxK

UR - http://dx.doi.org/10.1088/0953-8984/27/22/225401

U2 - 10.1088/0953-8984/27/22/225401

DO - 10.1088/0953-8984/27/22/225401

M3 - Article

VL - 27

JO - Journal of Physics: Condensed Matter

JF - Journal of Physics: Condensed Matter

SN - 0953-8984

IS - 22

M1 - 225401

ER -