Temperature dependence of the dielectric permittivity of CaF2, BaF2 and Al2O3: application to the prediction of a temperature dependent van der Waals surface interaction exerted onto a neighbouring Cs (8P{3/2}) atom

TL;DR

This study measures the infrared dielectric permittivity of CaF2, BaF2, and Al2O3 from 22°C to 500°C and uses these results to predict how temperature affects van der Waals interactions with a Cs (8P3/2) atom.

Contribution

It provides new temperature-dependent dielectric data for these materials and applies it to model atom-surface van der Waals interactions involving cesium atoms.

Findings

Dielectric permittivity varies with temperature in the studied range.

Predicted van der Waals interactions show temperature dependence.

Results aid in understanding atom-surface interactions at elevated temperatures.

Abstract

The temperature behaviour in the range 22\degree C to 500\degree C of the dielectric permittivity in the infrared range is investigated for CaF2, BaF2 and Al2O3 through reflectivity measurements. The dielectric permittivity is retrieved by fitting reflectivity spectra with a model taking into account multiphonon contributions. The results extrapolated from the measurements are applied to predict a temperature-dependent atom-surface van der Waals interaction. We specifically consider as the atom of interest Cs (8P3/2), the most relevant virtual couplings of which, fall in the range of thermal radiation and are located in the vicinity of the reststrahlen band of fluoride materials.