Extended Data Fig. 3: Stability of long acquisition times.
From: Operando probing of the surface chemistry during the Haber–Bosch process
a, The set of mass spectrometer data before any processing gathered over a 2-h window. The trend in masses 16, 17 and 18 are because of the slow improvement of the vacuum conditions. b, The same data as in a with processing as described in Methods. c, XPS spectra gathered simultaneously normalized to background signal. d, The sum of the spectra with the fitted peaks shown according to the colour scheme used throughout the paper.
