Molecular Bond Length Determination from σ Resonances in Near Edge Spectra

In recent years the K-shell excitation spectra of numerous gas phase molecules containing B, C, N, O and F have been studied by electron energy loss or photoabsorption spectroscopy. A common feature of these spectra is one or more relatively broad peaks in the region of the K-shell ionization threshold. Within a molecular orbital description these features may be attributed to ls → σ* transitions. Alternatively, they may be described as σ shape …