2007/03/02 by Michael Marek Koza, M. M. Koza, R. P. May +2 · 1 citation
Materials Science · Physics and Astronomy · #Glass properties and applications #Material Dynamics and Properties #Theoretical and Computational Physics #cond-mat.dis-nn #cond-mat.soft
paper · pdf · doi:10.1107/s0021889807004992
published as J. Appl. Cryst. 40, s517-s521, (2007)
openalex publication_date 2007/03/02 · arxiv created 2007/06/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
In this paper we report in situ small-angle neutron scattering results on the high-density amorphous (HDA) and low-density amorphous (LDA) ice structures and on intermediate structures as found during the temperature-induced transformation of HDA into LDA. We show that the small-angle signal is characterized by two Q regimes featuring different properties [Q is the modulus of the scattering vector defined as Q = (4π/λ\rm i)sin(θ) with θ being half the scattering angle and λ\rm i the incident neutron wavelength]. The very low Q regime (\lt ∼ 5× 10-2 Å−1) is dominated by a Porod-limit scattering. Its intensity reduces during the course of the HDA-to-LDA transformation following kinetics reminiscent of those observed in wide-angle diffraction experiments. The small-angle neutron scattering form factor in the intermediate regime of 5 × 10-2 \lt Q \lt 0.5 Å−1 for HDA and LDA features a rather flat plateau. However, the HDA signal shows an ascending intensity towards smaller Q marking this amorphous structure as heterogeneous. When following the HDA-to-LDA transition, the form factor shows a pronounced transient excess in intensity marking all intermediate structures as strongly heterogeneous on a length scale of some nanometres.