Identification of resonant excitation and shakeoff contributions to the CKVVAuger line shapes of several gas phase hydrocarbons

摘要

We have consistently interpreted the CKVVAuger line shapes of five hydrocarbons (methane, ethane, cyclohexane, benzene, and ethylene) and compared the results with those previously reported for three different solids (polyethylene, diamond, and graphite). We show that an interpretation procedure normally used for solids, namely, a selfhyphen;fold of the onehyphen;electron DOS and incorporation of holendash;hole correlation effects utilizing the Cini expression, is also adequate for molecules, and thus direct comparison of the gas phase and solid phase results is possible. In contrast to the solids, the normalkvvline shape accounts for only about half of the total experimental intensity for the gas phase molecules. The remaining part of the experimental line shape can be attributed to three different satellite contributions; namely resonant excitation (kendash;vve), initialhyphen;statendash;shake (kvndash;vvv), and finalhyphen;statendash;shake (kndash;vvv) satellites. The normalkvvAuger line shapes are seen to reflect delocalized holes, however correlation effects are evident. In contrast, the threehyphen;hole final state of thekvndash;vvvprocess reflects holes localized primarily on a single methyl group. The results indicate that long range polarization effects are not important in the extended solids; short range pgr; electron screening is important in the alkenes and in graphite.