D. T. Larson’s research while affiliated with Dow Chemical Company and other places

... For thin film thickness measurements, the spectral reflectometer has been widely employed due to high measurement speed and simple configuration [3][4][5][6][7]12,14 . The lights reflected from the top and bottom surfaces interfere with each other, as shown in Fig. 1. ...

Reference:

A novel method to design and evaluate artificial neural network for thin film thickness measurement traceable to the length standard

... 9,10 Unlike the reactive metallic plutonium carbide compound, for which photoemission data have shown itinerant 5f behavior, 11 plutonium oxycarbide surface films have shown to be unreactive and offer oxidation resistance or protection to δ-Pu alloys. 12,13 Prior to chemical analysis, plutonium oxycarbide surface films were thought to be the homoleptic monoxide phase, "PuO," 14 but first principles calculations have since shown this to be unstable. 15 As both PuC 1−x and the oxycarbide are isostructural with the rock salt structure, 16 the contrasting chemical reactivity of these two compounds may be due to the differences in the Pu 5f electron behavior and concomitant electronic structure. ...

Reference:

Photoemission study of plutonium oxycarbide

... In earlier studies with SR, the theoretical reflectance spectrum was modeled by considering only the reflection and transmission under the assumption that the absorptivity of the material is negligible. However, because the absorptivity cannot be ignored depending on the material, various methods adopting the complex refractive index instead of the real refractive index have been studied in an effort to realize a more accurate model of the theoretical reflectance spectrum, even when the absorptivity is quite low [6,7,[9][10][11][12][13][14][15]18]. From this line of research, a more accurate model of the reflectance spectrum can be created by considering the absorption effect quantitatively, thus facilitating thin-film thickness measurements with greater accuracy. ...

Reference:

A Review of Thin-film Thickness Measurements using Optical Methods