- Email: [email protected]
Formation of CHx species on a Ni(100) surface by the hydrogenation of carbidic carbon
A235 Surface Science 283 (1993) 101-108 North-Holland
Spatial and velocity distributions of product desorption in carbon monoxide oxidation over palladium (110) and reconstructed platinum ( 110)(lx2) surfaces Tatsuo Matsushima Catalysis Research Center, Hokkaido University, Sapporo 060, Japan
Kosuke Shobatake and Yuichi Ohno Institute for Molecular Science, Myodaiji, Okazaki 444, Japan Received 20 April 1992; accepted for publication 18 May 1992 The spatial and velocity distributions of desorbing products were measured in the CO oxidation on Pd(ll0) and reconstructed Pt(ll0)(1 x 2) surfaces by means of a cross-correlation time-of-flight technique combined with angle-resolved thermal desorption. On Pd(ll0), a clear anisotropy was observed in both distributions. It is well correlated with the reaction site symmetry. On Pt(ll0)(1 x 2), both the desorption flux of CO 2 and the translational temperature are maximized around the terrace normal, confirming that the reaction occurs on declining terraces.
Surface Science 283 (1993) 109-116 North-Holland
Dynamics of pulsed ultraviolet laser enhancement of the chlorine-Si(lll) reaction T.N. Rhodin, C. Paulsen-Boaz and W.L. O'Brien School of Applied and Engineering Physics and Department of Chemistry, Cornell University, Ithaca NY 14853, USA Received 21 April 1992; accepted for publication 1 August 1992 New time-of-flight and surface microcharacterization instrumentation have been applied to the study of the critical factors in the ultraviolet photon enhanced chlorine reaction on a well characterized surface of Si(111). The importance of carrier doping and wavelength were of particular interest. The reaction mechanism is discussed in terms of similarities and differences between previous laser-enhanced etching rate studies and photon-enhanced mechanisms based on the photon generation and transport of electron-holes to the surface followed by interaction with the substrate-adsorbate complex. Interpretation of the carrier-doping and wavelength dependence in terms of the model proposed by Ying and Ho for the N O / S i ( l l l ) 7 x 7 system, to C I / S i ( l l l ) has been partly successful.
Surface Science 283 (1993) 117-120 North-Holland
Formation of CH x species on a Ni(100) surface by the hydrogenation of carbidic carbon Hong He, Junji Nakamura 1 and Ken-ichi Tanaka Institute for Solid State Physics, University of Tokyo, 7-22-1 Roppongi, Minato-ku, Tokyo 106, Japan Received 21 April 1992; accepted for publication 15 July 1992 We have investigated the formation of CH x species by the reaction of p4g carbide with hydrogen on the Ni(100) surface. The CH x species were directly detected using high resolution electron energy loss spectroscopy (HREELS). After hydrogenation of the surface carbide with 1 x 10 -7 Torr of H 2 at 313 K, two loss peaks at 2970 and 1380 cm -1 were observed which indicates the formation of CH x on the surface. The CHx species undergoes decomposition at 330-370 K in UHV and in 1 x 10 -7 Torr H 2. Isotope exchange of the CH~ with D E is slower than the formation of CH x from carbide by at least one order of magnitude.
Spatial and velocity distributions of product desorption in carbon monoxide oxidation over palladium (110) and reconstructed platinum ( 110)(lx2) surfaces Tatsuo Matsushima Catalysis Research Center, Hokkaido University, Sapporo 060, Japan
Kosuke Shobatake and Yuichi Ohno Institute for Molecular Science, Myodaiji, Okazaki 444, Japan Received 20 April 1992; accepted for publication 18 May 1992 The spatial and velocity distributions of desorbing products were measured in the CO oxidation on Pd(ll0) and reconstructed Pt(ll0)(1 x 2) surfaces by means of a cross-correlation time-of-flight technique combined with angle-resolved thermal desorption. On Pd(ll0), a clear anisotropy was observed in both distributions. It is well correlated with the reaction site symmetry. On Pt(ll0)(1 x 2), both the desorption flux of CO 2 and the translational temperature are maximized around the terrace normal, confirming that the reaction occurs on declining terraces.
Surface Science 283 (1993) 109-116 North-Holland
Dynamics of pulsed ultraviolet laser enhancement of the chlorine-Si(lll) reaction T.N. Rhodin, C. Paulsen-Boaz and W.L. O'Brien School of Applied and Engineering Physics and Department of Chemistry, Cornell University, Ithaca NY 14853, USA Received 21 April 1992; accepted for publication 1 August 1992 New time-of-flight and surface microcharacterization instrumentation have been applied to the study of the critical factors in the ultraviolet photon enhanced chlorine reaction on a well characterized surface of Si(111). The importance of carrier doping and wavelength were of particular interest. The reaction mechanism is discussed in terms of similarities and differences between previous laser-enhanced etching rate studies and photon-enhanced mechanisms based on the photon generation and transport of electron-holes to the surface followed by interaction with the substrate-adsorbate complex. Interpretation of the carrier-doping and wavelength dependence in terms of the model proposed by Ying and Ho for the N O / S i ( l l l ) 7 x 7 system, to C I / S i ( l l l ) has been partly successful.
Surface Science 283 (1993) 117-120 North-Holland
Formation of CH x species on a Ni(100) surface by the hydrogenation of carbidic carbon Hong He, Junji Nakamura 1 and Ken-ichi Tanaka Institute for Solid State Physics, University of Tokyo, 7-22-1 Roppongi, Minato-ku, Tokyo 106, Japan Received 21 April 1992; accepted for publication 15 July 1992 We have investigated the formation of CH x species by the reaction of p4g carbide with hydrogen on the Ni(100) surface. The CH x species were directly detected using high resolution electron energy loss spectroscopy (HREELS). After hydrogenation of the surface carbide with 1 x 10 -7 Torr of H 2 at 313 K, two loss peaks at 2970 and 1380 cm -1 were observed which indicates the formation of CH x on the surface. The CHx species undergoes decomposition at 330-370 K in UHV and in 1 x 10 -7 Torr H 2. Isotope exchange of the CH~ with D E is slower than the formation of CH x from carbide by at least one order of magnitude.