The HCNH and CNH2 adsorption on different coordination sites of Cu（100） was theoretically studied considering the cluster approach. The present calculations show that the bridge site is the most favorite for CNH2 pe...The HCNH and CNH2 adsorption on different coordination sites of Cu（100） was theoretically studied considering the cluster approach. The present calculations show that the bridge site is the most favorite for CNH2 perpendicularly adsorbed on the Cu（100） surface via the C atom. For HCNH absorbed on the Cu（100） surface, the parallel adsorption mode with the C and N atoms nearly directly above the adjacent top sites of Cu（100） surface is the most favored. Both CNH2 and HCNH are strongly bound to the Cu（100） surface with CNH2 which is lightly stable （2.51 kJ·mol^-1）, indicating that both species may be co-adsorbed on the Cu（100） surface.展开更多
The adsorption and reaction of O ＋ CN → OCN on Cu（100） are studied by using density functional theory and cluster model. Cu14 cluster model is used to simulate the surface. The calculated results show that the OCN...The adsorption and reaction of O ＋ CN → OCN on Cu（100） are studied by using density functional theory and cluster model. Cu14 cluster model is used to simulate the surface. The calculated results show that the OCN species with the molecule perpendicular to the surface via N atom （N-down） is more favorable than other adsorption models, and the N-down at the bridge site is the most favorable. For N-down, calculated OCN symmetric and asymmetric stretching frequencies are all blue-shifted compared with the calculated values of free and in good agreement with the experiments. The charge transfer from the surface to the OCN species leads to that the bonding of OCN to the metal surface is largely ionic. The present studies also show that CN with the molecule perpendicular to the surface via C atom （NC-down） at the top site is the most stable. Except NC-down at the top site, the calculated CN stretching frequencies are all red-shifted. With O coadsorbed at the hollow site, the adsorption of NC-down at the next nearest bridge or top site is energetically more favorable than that at the adjacent hollow site. The reaction of O ＋ CN → OCN on Cu（100） has no energy barrier via both Eley-Rideal and Langmuir-Hinshelwood processes.展开更多
The interaction of atomic oxygen with the clean Cu（100） surface has been studied by means of cluster and periodic slab models density functional theory in the present paper. The Cu（4,9,4） cluster and a three-layer...The interaction of atomic oxygen with the clean Cu（100） surface has been studied by means of cluster and periodic slab models density functional theory in the present paper. The Cu（4,9,4） cluster and a three-layer slab with c（2×2） structure are used to model the perfect Cn（100） surface. Three possible adsorption sites, top, bridge and hollow site, were considered in the calculations. The predicted results show that the hollow site is the prefer site for atomic oxygen adsorbed on Cu（100） surface energetically. This is in good agreement with the experiment. The calculated binding energies are respective 2.014, 3.154 and 3.942 eV for top, bridge and hollow sites at mPW1PW91/LanL2dz level for the cluster model. The geometry of Cu（100） surface has also been optimized theoretically with various density functional rnethods and the results show that the prediction from the B3PW91/LanL2dz and mPWlPW91/LanL2dz reproduce the experimental observation. The frontier molecular orbitals and partial density of states analysis show that the electron transfer from the d orbital of substrate to the p orbital of the surface oxygen atom.展开更多
A generalized LEPS potential energy surface of (H_2?H +H)/Li(100) plane systemwas constructed based on the ab initio SCF absorption and surface diffusion of a hydrogenatom on lithium(100) surface, and reaction kinetic...A generalized LEPS potential energy surface of (H_2?H +H)/Li(100) plane systemwas constructed based on the ab initio SCF absorption and surface diffusion of a hydrogenatom on lithium(100) surface, and reaction kinetic behaviour of this system was investigatedby means of QCT method. It was shown from analysis of the feature of this potential energysurface that the activation energy of absorption of H_2 molecules on a lithium(100) planeis unnecessary and the dissociation of H_2 on the Li(100) plane relates closely to the adsorp-tion sites and adsorption fashions, and the horizontal manner of dissociation of H_2 is easierthan the standing one. And it was also shown from the analysis of various collision trajec-tories that the surface recombination probabilities of bi-hydrogen atoms at low covering arevery small, and that the surface dissociation probabilities of H_2 are controlled by its vibra-tional quantum number. The potential energy surface of gas-metal surface interaction systemconstructed here is convenient to study on reaction dynamics, and a good explanation forcrossed molecular beam experiments of surface activation of H_2 molecule can be offered byQCT kinetic calculations in this work.展开更多
基金the National Natural Science Foundation of China(20673019,20773024)the Science Foundation of Fujian Province (2006J0256, Z0513005)the Funding of Fuzhou University(XRC-0732, 2008-XQ-07)
文摘The HCNH and CNH2 adsorption on different coordination sites of Cu（100） was theoretically studied considering the cluster approach. The present calculations show that the bridge site is the most favorite for CNH2 perpendicularly adsorbed on the Cu（100） surface via the C atom. For HCNH absorbed on the Cu（100） surface, the parallel adsorption mode with the C and N atoms nearly directly above the adjacent top sites of Cu（100） surface is the most favored. Both CNH2 and HCNH are strongly bound to the Cu（100） surface with CNH2 which is lightly stable （2.51 kJ·mol^-1）, indicating that both species may be co-adsorbed on the Cu（100） surface.
基金This research was supported by the National Natural Science Foundation of China (20273013, 20303002), the Educational Foundation of Fujian Province (2002F010), and the Foundation of State Key Laboratory of Structural Chemistry (020051) and Fuzhou University (2004XY04)
文摘The adsorption and reaction of O ＋ CN → OCN on Cu（100） are studied by using density functional theory and cluster model. Cu14 cluster model is used to simulate the surface. The calculated results show that the OCN species with the molecule perpendicular to the surface via N atom （N-down） is more favorable than other adsorption models, and the N-down at the bridge site is the most favorable. For N-down, calculated OCN symmetric and asymmetric stretching frequencies are all blue-shifted compared with the calculated values of free and in good agreement with the experiments. The charge transfer from the surface to the OCN species leads to that the bonding of OCN to the metal surface is largely ionic. The present studies also show that CN with the molecule perpendicular to the surface via C atom （NC-down） at the top site is the most stable. Except NC-down at the top site, the calculated CN stretching frequencies are all red-shifted. With O coadsorbed at the hollow site, the adsorption of NC-down at the next nearest bridge or top site is energetically more favorable than that at the adjacent hollow site. The reaction of O ＋ CN → OCN on Cu（100） has no energy barrier via both Eley-Rideal and Langmuir-Hinshelwood processes.
基金This work was supported by National Natural Science Foundation of China （NSFC No. 20273013） and Pujian Provincial Department of Education （No. JA03020）
文摘The interaction of atomic oxygen with the clean Cu（100） surface has been studied by means of cluster and periodic slab models density functional theory in the present paper. The Cu（4,9,4） cluster and a three-layer slab with c（2×2） structure are used to model the perfect Cn（100） surface. Three possible adsorption sites, top, bridge and hollow site, were considered in the calculations. The predicted results show that the hollow site is the prefer site for atomic oxygen adsorbed on Cu（100） surface energetically. This is in good agreement with the experiment. The calculated binding energies are respective 2.014, 3.154 and 3.942 eV for top, bridge and hollow sites at mPW1PW91/LanL2dz level for the cluster model. The geometry of Cu（100） surface has also been optimized theoretically with various density functional rnethods and the results show that the prediction from the B3PW91/LanL2dz and mPWlPW91/LanL2dz reproduce the experimental observation. The frontier molecular orbitals and partial density of states analysis show that the electron transfer from the d orbital of substrate to the p orbital of the surface oxygen atom.
基金Project supported by the National Natural Science Foundation of China.
文摘A generalized LEPS potential energy surface of (H_2?H +H)/Li(100) plane systemwas constructed based on the ab initio SCF absorption and surface diffusion of a hydrogenatom on lithium(100) surface, and reaction kinetic behaviour of this system was investigatedby means of QCT method. It was shown from analysis of the feature of this potential energysurface that the activation energy of absorption of H_2 molecules on a lithium(100) planeis unnecessary and the dissociation of H_2 on the Li(100) plane relates closely to the adsorp-tion sites and adsorption fashions, and the horizontal manner of dissociation of H_2 is easierthan the standing one. And it was also shown from the analysis of various collision trajec-tories that the surface recombination probabilities of bi-hydrogen atoms at low covering arevery small, and that the surface dissociation probabilities of H_2 are controlled by its vibra-tional quantum number. The potential energy surface of gas-metal surface interaction systemconstructed here is convenient to study on reaction dynamics, and a good explanation forcrossed molecular beam experiments of surface activation of H_2 molecule can be offered byQCT kinetic calculations in this work.
