軟Ｘ線吸収分光法や軟Ｘ線発光分光法は、元素選択した局所的な電子構造を測定することができる。すなわち、これらの分光法用いれば、固体表面分子吸着系の表面化学結合部位の電子構造を調べることができる。本研究では、Si(100)2×１表面上にC₂H₄を単層吸着させた系について実験結果を報告する。

We have studied the surface chemical bonding of well-defined C₂H₄ adsorbate on Si(100)(2x1) surface using Soft X-ray absorption spectroscopy (XAS) and soft X-ray emission spectroscopy (XES). The unique strengh of XES applied to adsorbates is a local and atom specific projection of the occupied adsorbate valence electronic state is obtained, where the contribution from overlapping valence states of the much larger number of atoms in the substrate is negligible. Complementary information on the unoccupied adsorbate electronic structure can be obtained by XAS.