Multivacancy effects in the x-ray spectra ofCH3Cl

Abstract

A high-efficiency x-ray spectrometer has been constructed with use of a curved crystal and a position-sensitive detector mounted along a Rowland circle. Results obtained for the Cl K absorption and fluorescent Kβ emission of molecular ${\mathrm{CH}}_3$Cl show previously unobtainable details. The gas target is excited by primary radiation from a demountable conventional x-ray tube. The use of different anode materials and the insertion of filters between x-ray source and target allow some variation of the primary excitation energy. By monitoring emission spectra for different primary excitation energies, we are able to attribute the newly observed absorption features to multivacancy excitations. Such modulations in the suprathreshold absorption cross section would complicate the extraction of structural information in an extended x-ray-absorption fine-structure (EXAFS) analysis.