Results for “LuF3” | Engineering Papers

DOE OSTI2020

Materials Data on LuF3 by Materials Project

LuF3 is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Lu3+ is bonded in a distorted body-centered cubic geometry to fourteen F1- atoms. There are eight shorter (2.37 Å) and six longer (2.74 Å) Lu–F bond lengths. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded to four equivalent Lu3+ and four equivalent F1- atoms to form a mixture of edge, face, and corner-sharing FLu4F4 tetrahedra. All F–F bond lengths are 2.37 Å. In the second F1- site, F1- is bonded in a 6-coordinate geometry to six equivalent Lu3+ and eight equivalent F1- atoms.

36 MATERIALS SCIENCE↗

NASA NTRS2014

Enhanced Fluoride Over-Coated Al Mirrors for FUV Astronomy

Astronomical observations in the Far Ultraviolet (FUV) spectral region are some of the more challenging due to the very distant and faint objects that are typically searched for in cosmic origin studies such as origin of large scale structure, the formation, evolution, and age of galaxies and the origin of stellar and planetary systems. These challenges are driving the need to improve the performance of optical coatings over a wide spectral range that would increase reflectance in mirrors and reduced absorption in dielectric filters used in optical telescope for FUV observations. This paper will present recent advances in reflectance performance for Al+MgF2 mirrors optimized for Lyman-alpha wavelength by performing the deposition of the MgF2 overcoat at elevated substrate temperatures. We will also present optical characterization of little studied rare-earth fluorides such as GdF3 and LuF3 that exhibit low-absorption over a wide wavelength range and could therefore be used as high refractive index alternatives for dielectric coatings at FUV wavelengths.

Reflectance↗

NASA NTRS2014

Recent Progress on 2012 SAT for UVOIR Coatings

Astronomical observations in the Far Ultraviolet (FUV) spectral region are some of the more challenging due to the very distant and faint objects that are typically searched for in cosmic origin studies such as origin of large scale structure, the formation, evolution, and age of galaxies and the origin of stellar and planetary systems. These challenges are driving the need to improve the performance of optical coatings over a wide spectral range that would increase reflectance in mirrors and reduced absorption in dielectric filters used in optical telescope for FUV observations. This paper will present recent advances in reflectance performance for Al+MgF2 mirrors optimized for Lyman-alpha wavelength by performing the deposition of the MgF2 overcoat at elevated substrate temperatures. We will also present optical characterization of little studied rare-earth fluorides such as GdF3 and LuF3 that exhibit low-absorption over a wide wavelength range and could therefore be used as high refractive index alternatives fordielectric coatings at FUV wavelengths.

LiF↗