Effects of background gas composition and pressure on 1,4-polymyrcene (and polytetrafluoroethylene) spectra in near-ambient pressure XPS

Near-ambient pressure XPS (NAP-XPS) is a less traditional form of XPS that allows samples to be analyzed at relatively high pressures, i.e., at 2500 Pa or greater. With NAP-XPS, one can analyze moderately volatile liquids, biological samples, porous materials, and/or polymeric materials that outgas significantly. In this submission, the authors show C 1s, O 1s, and survey NAP-XPS spectra from 1,4-polymyrcene. The C 1s and O 1s envelopes are fit with Gaussian–Lorentzian product, asymmetric Lorentzian, and Gaussian–Lorentzian sum functions. Water vapor and argon are used to control sample charging, and the corresponding signals from the gases are present in the survey spectra. The effect of background gas pressure on photoelectron attenuation is illustrated with a sample of polytetrafluoroethylene.