Atomic and electronic structure of acetic acid on Ge(1 0 0) |
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Authors: | Do Hwan Kim Eunkyung Hwang Sehun Kim |
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Institution: | a Department of Chemistry and School of Molecular Science (BK21), Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea b Department of Physics and Institute of Fundamental Physics, Sejong University, Seoul 143-747, Republic of Korea |
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Abstract: | We have performed ab initio density-functional theory (DFT) calculations in order to investigate the atomic and electronic structure of acetic acid adsorbed on Ge(1 0 0) surface. Due to its acidity, acetic acid dissociates and the resulting electron-rich acetate group reacts with the electron-deficient down-Ge atom through nucleophilic addition (mono-dentate structure). Further reaction between the electron-rich up-Ge atom and the carboxylic oxygen atom results in bidentate bridged structures, which are energetically most favorable among the tested geometries. The existence of the dissociated H atom on the neighboring Ge atoms and the buckling of Ge dimers are found to affect the feasibility of the formation of bidentate structures. We obtain the simulated STM images from the optimized adsorption geometries for most favorable structures. Theoretical STM images for on-top bidentate structures show characteristic features having on-top protrusions, while those for end-bridged structures show protrusions localized at one side of a dimer row. |
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Keywords: | Density-functional theory calculations Germanium Acetic acid Chemisorption Ge(1 0 0) Atomic and electronic structure |
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