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Refractive index and density of vapor‐deposited ice
Author(s) -
Berland B. S.,
Brown D. E.,
Tolbert M. A.,
George S. M.
Publication year - 1995
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/95gl03504
Subject(s) - refractive index , materials science , substrate (aquarium) , analytical chemistry (journal) , torr , diffusion , optics , chemistry , thermodynamics , physics , geology , optoelectronics , oceanography , chromatography
The refractive indices of vapor‐deposited ice films were measured versus substrate temperature from 35–140 K and H 2 O pressure from 1.9 × 10 −7 –9.5 × 10 −5 Torr using optical interference techniques. The refractive indices were measured for ice films deposited on a cooled, single‐crystal Al 2 O 3 substrate in vacuum. Ice densities were calculated from these refractive indices using the Lorentz‐Lorenz relationship. Above 120 K, the ice films had a refractive index of n=1.31 and a density of ρ=0.93 g/cm³. Significantly lower refractive indices and densities were found at lower temperatures and higher H 2 O fluxes that were consistent with microporous ices. A refractive index of n=1.24 and density of ρ=0.68 g/cm³ were determined at 35 K and an H 2 O pressure of 4 × 10 −6 Torr. Above 35 K, the refractive index and density progressively increased with increasing temperature and decreasing H 2 O flux. The ice densities observed can be explained qualitatively using a ballistic deposition model. Estimates are also obtained for the surface diffusion of H 2 O on vapor‐deposited ice.