Density and index of refraction of water ice films vapor deposited at low temperatures

The density of 0.5–3 μm thick vapor-deposited films of water ice were measured by combined optical interferometry and microbalance techniques during deposition on an optically flat gold substrate from a capillary array gas source. The films were of high optical quality with an index of refraction of 1.29±0.01 at 435.8 nm, a density of 0.82±0.01 g/cm3, and a porosity of 0.13±0.01. In contrast to previous studies, none of the measured properties exhibited any significant variation with growth rate or temperature over the range studied (0.6–2 nm/min, 20–140 K).