See Estes el al. (2019) for complete methods.
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1\u201310 \u03bcL of standard compounds was pipetted onto silicon wafers and air-dried. The beamline was operated with a 500 l mm\u20131 spherical grating monochromator and entrance and exit slits set to 40 \u03bcm, which yielded an absolute energy resolution of less than 0.3 eV. The samples were attached to an aluminium sample stick in a single load and analysed under ultrahigh vacuum conditions (pressure ~10\u22129 mbar). The measurements were made in the total electron yield (TEY) mode on a spot size of less than 1 mm2 using a grazing incidence angle of 45\u00b0, where previous trials determined that the incidence angle did not yield a
\ndifference in results. The TEY mode was selected instead of fluorescence as we observed dampening of the fluorescence signal, probably due to matrix-induced absorption.
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Spectra were collected around the C 1s edge, from 260 to 340 eV, with a dwell time of 0.2 s. To avoid beam damage and variation of the background due to charging, scans were taken at different positions on the sample. The spectra analysed were the average of 2\u20133 scans taken at different positions on the sample. The dark current was measured prior to the collection of each spectrum and subtracted from the raw data. Spectra were then normalized to no load current measured by a mesh upstream of the chamber with freshly evaporated gold.
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Instruments:
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Bulk carbon NEXAFS spectroscopy was conducted on beamlines 8-2 and 10-1 at the Stanford Synchrotron Radiation Lightsource.
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The absolute energy calibration of the carbon spectra was achieved by shifting the energy such that the first dip in the incoming intensity due to carbon contamination on the beamline optics (carbon dip) occurred at 284.7 eV.
Carbon near edge X-ray absorption fine structure (NEXAFS) spectra of standard compounds.\u00a0 These data contain incident energy and\u00a0absorption values at that energy for a standard compounds.
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These data were published in Estes et al. (2019).
Spectral processing was completed by subtracting a line fit to the pre-edge region (281\u2013283 eV), followed by an area normalization between 282 and 310 eV with the high-energy intensity kept constant (atomic normalization). The entire pre-edge region appeared linear; fitting and background subtraction was conducted over a smaller energy range due to the presence of oxygen harmonic peaks. All the data normalization was conducted in Igor Pro (WaveMetrics).
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BCO-DMO Data Manager Processing Notes:
\n* exported data in xlsx file \"Estes_NEXAFSstds_data.xlsx\" to csv file
\n* added a conventional header with dataset name, PI name, version date
\n* modified parameter names to conform with BCO-DMO naming conventions
\n* blank values in this dataset are displayed as \"nd\" for \"no data.\"\u00a0 nd is the default missing data identifier in the BCO-DMO system.