Fig. 2: Locating trapped molecules with NIXSW.
From: Chemical shielding of H2O and HF encapsulated inside a C60 cage
a Diagram of the NIXSW technique where an X-ray standing wave is established at the sample surface by tuning hν close to the crystal Bragg condition. b O 1s core-level photoemission spectrum (hν = 700eV) and c F 1s level (hν = 900 eV) for H2O@C60 and HF@C60, respectively, confirming the presence of the encapsulated molecules in the monolayer film. d NIXSW data for H2O@C60 with insets: bulk Ag NIXSW and low-energy electron diffraction (LEED, E = 46.5 eV). Fitting analysis results in a coherent position and coherent fraction of Pc = 0.35 ± 0.03 and Fc = 0.78 ± 0.05, respectively. e NIXSW data for HF@C60. Fitting analysis results in a coherent position and coherent fraction of Pc = 0.43 ± 0.03 and Fc = 0.72 ± 0.07, respectively. Inset, LEED (E = 50.5 eV). LEED confirms both samples are prepared as a single layer (2\(\sqrt{3}\) × 2\(\sqrt{3}\))R30° molecular superlattice on Ag(111). The NIXSW data were acquired at 20 K at the Ag{111} Bragg energy. Y-axis error bars in d and e are determined from fits of the O 1s and F 1s spectra used to determine relative absorption.
