Preliminary Evaluation of Capabilities of A 5M Grating Spectrograph for the Production of High Resolution Molecular X-Ray Fluorescence Spectra in the Ultra Soft X-Ray Region

X-ray emission spectroscopy (XES) represents one of the many ways of obtaining useful information about the valence electron structures of molecules.(1) XES has had increasing attention as a molecular tool since the late 1960's.(2) Most of the earlier experiments have dealt with observations of Kβ transitions, i.e. observations below 10 A utilizing crystal optics. With curved crystal, and/or with double crystal optics the instrumental resolution is somewhere between 0.5 to 0.75 eV.(3) In more recent years molecular X-ray spectroscopy has begun to focus on transitions above 10 A where grating optics become useful with instrumental resolution being 0.1 eV or less thus yielding truly high resolution capabilities.(4,5) Above 10 A in the so-called ultra