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Core-level Spectra (core-level + spectrum)
Selected AbstractsBond cutting in K-doped tris(8-hydroxyquinoline) aluminiumJOURNAL OF SYNCHROTRON RADIATION, Issue 5 2008Hsin-Han Lee A series of Al 2p, K 2p, O 1s and N 1s core-level spectra have been used to characterize the interaction between potassium (K) and tris(8-hydroxyquinoline) aluminium (Alq3) molecules in the K-doped Alq3 layer. All core-level spectra were tuned to be very surface sensitive in selecting various photon energies provided by the wide-range beamline at the National Synchrotron Radiation Research Center, Taiwan. A critical K concentration (x = 2.4) exists in the K-doped Alq3 layer, below which the K-doped atoms generate a strained environment near the O and N atoms within 8-quinolinoline ligands. This creates new O 1s and N 1s components on the lower binding-energy side. Above the critical K coverage, the K-doped atoms attach the O atoms in the Al,O,C bonds next to the phenoxide ring and replace Al,O,C bonds by forming K,O,C bonds. An Alq3 molecule is disassembled into Alq2 and Kq by bond cutting and bond formation. The Alq2 molecule can be further dissociated into Alq, or even Al, through subsequent formations of Kq. [source] The Adsorption Configuration of Valine on Ge(100)CHEMPHYSCHEM, Issue 2 2010Young-Sang Youn The adsorption geometry of valine on a Ge(100) surface was studied using high-resolution core-level photoemission spectroscopy. Analysis of Ge,3d, C,1s, N,1s, and O,1s core-level spectra of valine adsorbed onto the Ge(100) surface suggests that both the amine and carboxyl groups in valine concurrently participate in the adsorption (see picture). [source] Spectroscopic Characteristics of Differently Produced Single-Walled Carbon NanotubesCHEMPHYSCHEM, Issue 13 2009Zhongrui Li Prof. Dr. Abstract Single-walled carbon nanotubes (SWNTs) synthesized with different methods are investigated by using multiple characterization techniques, including Raman scattering, optical absorption, and X-ray absorption near edge structure, along with X-ray photoemission by following the total valence bands and C 1s core-level spectra. Four different SWNT materials (produced by arc discharge, HiPco, laser ablation, and CoMoCat methods) contain nanotubes with diameters ranging from 0.7 to 2.8 nm. The diameter distribution and the composition of metallic and semiconducting tubes of the SWNT materials are strongly affected by the synthesis method. Similar sp2 hybridization of carbon in the oxygenated SWNT structure can be found, but different surface functionalities are introduced while the tubes are processed. All the SWNTs demonstrate stronger plasmon resonance excitations and lower electron binding energy than graphite and multiwalled carbon nanotubes. These SWNT materials also exhibit different valence-band X-ray photoemission features, which are considerably affected by the nanotube diameter distribution and metallic/semiconducting composition. [source] Adsorption of CO2 and Coadsorption of H and CO2 on Potassium-Promoted Cu(115)CHEMPHYSCHEM, Issue 5 2003Jens Onsgaard Prof. Dr. Abstract The influence of potassium, in the submonolayer regime, on the adsorption and coadsorption of CO2and H on a stepped copper surface, Cu(115), has been studied by photoelectron spectroscopy, temperature-programmed desorption, and work-function measurements. Based on the fast recording of C 1s and O 1s core-level spectra, the uptake of CO2on K/Cu(115) surfaces at 120 K has been followed in real time, and the different reaction products have been identified. The K 2p3/2peak exhibits a chemical shift of ,0.4 eV with CO2saturation, the C 1s peaks of the CO3and the CO species show shifts of ,0.8 and ,0.5 eV, respectively, and the C 1s peak of the physisorbed CO2exhibits no shift. The effects of gradually heating the CO2/K/Cu(115) surface include the desorption of physisorbed CO2at 143 K; the desorption of CO at 193 K; the ordering of the CO3species, and subsequently the dissociation of the carbonate with desorption at 520,700 K. Formate, HCOO,, was synthesized by the coadsorption of H and CO2on the K/Cu(115) surface at 125 K. Formate formed exclusively for potassium coverages of less than 0.4 monolayer, whereas both formate and carbonate were formed at higher coverages. The desorption of formate-derived CO2took place in the temperature range 410,425 K and carbonate-derived CO2desorbed at 645,660 K, depending on the potassium coverage. [source] | ||||||||||