Study of Water Adsorption on Organics Crystal Surfaces Using a Modified X-ray Photoelectron Spectroscopy Instrument

摘要

ABSTRACT: The coupling of a high partial pressure waternvapor system to a conventional X-ray photoelectron spec-ntroscopy instrument for use with both organic powders andnsingle crystals is described. Themodified chamber serves a dualnpurpose as both a treatment and sample preparation apparatus.nThe design utilizes the high- and cryo-temperature capabilitiesnof the existing system to allow investigation of various states ofnsurface water, as well as the interplay between temperature,nwater, and surface structure of the substrate. Sample handlingnand methods for compatibility testing are detailed, and datanillustrating the application of the modified and integratedncapabilities are summarized, detailing novel studies on the state of water on the surface of model organic pharmaceutical salts.nIn addition to facilitating investigation of the presence of various states of water at the surface of organic material, namely, dissociatednversus molecular water, the setup allows the investigation of structural effects of the surface on the state of water.