A new technique for determining the refractive index of ices at cryogenic temperatures

Abstract

A novel reflection-absorption optical (RAO) spectrometer, operating across the ultra-violet/visible (UV/visible) wavelength region, has been developed that allows simultaneous measurements of optical properties and thickness of thin solid films at...

Contrasting mechanisms for photodissociation of methyl halides adsorbed on thin films of C6H6 and C6F6

“…and on HOPG 25 . The near-UV absorption bands are observed to be shifted and broadened, with other modifications noted in the solid phase as compared to the gas-phase spectrum.…”

Detecting ultrathin ice on materials for optical coatings at cryogenic temperatures

“…The optical properties of ice have been studied in a number of different experimental conditions, including pressure, temperature, and spectral range [39][40][41][42]. The refractive index was found not to vary with the ice phase [42]; it decreasesalong with the density-with temperature [41].…”

“…The optical properties of ice have been studied in a number of different experimental conditions, including pressure, temperature, and spectral range [39][40][41][42]. The refractive index was found not to vary with the ice phase [42]; it decreasesalong with the density-with temperature [41]. In other words, ice formed at higher temperatures has a higher density and a higher refractive index with respect to ice formed at lower temperatures.…”

Refractive index and extinction coefficient of vapor-deposited water ice in the UV-Vis range

“…The Lorentz-Lorenz relation has been used by several groups to calculate the refractive index value for ASW, either directly or indirectly (Berland et al 1995;Brown et al 1996;Westley et al 1998;Dohnálek et al 2003;Kofman et al 2019;Stubbing et al 2020). As pointed by Dohnálek et al (2003), the validity of the Lorentz-Lorenz relation is based on the assumption that the film is homogeneous on the length scale set by the wavelength of the light.…”

“…The advantage of this method is that it allows measuring the refractive index value without relying on separate calibrations of the density or the Lorentz-Lorenz relation. The most recent development has been reported by Stubbing et al (2018Stubbing et al ( , 2020 who developed a new UHV-compatible UV-visible spectrometer that allows simultaneous measurement of thickness and refractive index of ices. Their setup has the capability to change the incidence angle of the light without making changes to the chamber.…”