Local bonding states of ion-irradiated graphite characterized by photon-stimulated desorption (PSD) spectroscopy

We investigated the local bonding states of D2 +-irradiated graphite using a photon-stimulated ion-desorption (PSID) technique, which incorporates polarized near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The carbon K-edge NEXAFS conducted in Auger electron yield mode showed no significant dependence on polarization angles (θ), while H+- and D+-PSID NEXAFS showed polarization-dependent resonances. The σ*(C—H) resonance in H+ ions and σ*(C—D) in D+ ions showed enhanced yields, which were larger at θ =10° than at θ =45° and the σ*(C＝C) peak in D+ ions showed a prominent enhancement which was stronger at θ =10° than at θ =45°. Our results are interpreted assuming that the difference in local structures between C—H and C—D bonds is reflected in the PSID NEXAFS. [Copyright &y& Elsevier]