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Deformation enhanced photoemission from oriented aluminum single crystal surfaces
A345 Surface Science 99 (1980) 3 5 6 - 3 7 2 © North-Holland Publishing Company SCATTERING OF HYDROGEN AND HELIUM FROM CESlATED SURFACES W. E C K S T E I N , H. V E R B E E K a n d R.S. B H A T T A C H A R Y A *
Max-Planck-lnstitut far Plasmaphysik, Euratom Association, D-8046 Garching, Germany Received 15 February 1980; accepted for publication 3 April 1980 Hydrogen and helium ion beams with energies of 1 to 15 keV have been reflected from Cs-covered Ni surfaces at normal incidence. For hydrogen there are surface peaks in the positive fraction and surface minima in the negative fraction, a result very different from that observed with other materials. The charged fractions of both hydrogen and helium depend on the thickness of the Cs layer. Some results for scattering of hydrogen at glancing angles are presented.
Surface Science 99 (1980) 373-383 ©North-Holland Publishing Company DEFORMATION ENHANCED PHOTOEMISSION FROM ORIENTED ALUMINUM SINGLE CRYSTAL SURFACES T.K.G. SWAMI a n d Y.W. C H U N G
Department o f Materials Sciene and Engineering, and Materials Research Center, Northwestern University, Evanston, Illinois 60201, USA Received 26 December 1979; accepted for publication 1 April 1980 Plastic-deformation-enhanced UV photoemission from oriented single crystal surfaces of aluminum has been studied. Clean single crystals of aluminum oriented in [ 111 ] direction were flexurally fatigued under UHV conditions and for the f'trst time photoelectron energy distribution curves were obtained as a function of fatigue life using the HeI (21.2 eV) and the Hell (40.8 eV) photon lines. The integrated photocurrent was measured as a function of fatigue life using the photon lines from helium and argon sources. A progressive decrease in work function was observed as the specimen was subjected to increasing number of fatigue cycles. At a strain amplitude of -+0.2%, a drop of 0.2 eV in the work function occurred after 3000 fatigue cycles. Further, significant changes in aluminum valence band emission as a result of fatigue have been observed along with the formation of slip-steps on the surface of the aluminum specimen as seen under the scanning electron microscope. This alteration in the surface microgeometry caused by fatigue is believed to be responsible for the observed changes in the work function and the electronic band structure. The change in the total integrated photoyield caused by fatigue is thus determined by work function and valence band changes.
Surface Science 99 (1980) 384-391 © North-Holland Publishing Company THEORETICAL DETERMINATION OF THE STRUCTURE OF ACETYLENE O N P t ( l 11) A l f r e d B. A N D E R S O N
Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA and
Max-Planck-lnstitut far Plasmaphysik, Euratom Association, D-8046 Garching, Germany Received 15 February 1980; accepted for publication 3 April 1980 Hydrogen and helium ion beams with energies of 1 to 15 keV have been reflected from Cs-covered Ni surfaces at normal incidence. For hydrogen there are surface peaks in the positive fraction and surface minima in the negative fraction, a result very different from that observed with other materials. The charged fractions of both hydrogen and helium depend on the thickness of the Cs layer. Some results for scattering of hydrogen at glancing angles are presented.
Surface Science 99 (1980) 373-383 ©North-Holland Publishing Company DEFORMATION ENHANCED PHOTOEMISSION FROM ORIENTED ALUMINUM SINGLE CRYSTAL SURFACES T.K.G. SWAMI a n d Y.W. C H U N G
Department o f Materials Sciene and Engineering, and Materials Research Center, Northwestern University, Evanston, Illinois 60201, USA Received 26 December 1979; accepted for publication 1 April 1980 Plastic-deformation-enhanced UV photoemission from oriented single crystal surfaces of aluminum has been studied. Clean single crystals of aluminum oriented in [ 111 ] direction were flexurally fatigued under UHV conditions and for the f'trst time photoelectron energy distribution curves were obtained as a function of fatigue life using the HeI (21.2 eV) and the Hell (40.8 eV) photon lines. The integrated photocurrent was measured as a function of fatigue life using the photon lines from helium and argon sources. A progressive decrease in work function was observed as the specimen was subjected to increasing number of fatigue cycles. At a strain amplitude of -+0.2%, a drop of 0.2 eV in the work function occurred after 3000 fatigue cycles. Further, significant changes in aluminum valence band emission as a result of fatigue have been observed along with the formation of slip-steps on the surface of the aluminum specimen as seen under the scanning electron microscope. This alteration in the surface microgeometry caused by fatigue is believed to be responsible for the observed changes in the work function and the electronic band structure. The change in the total integrated photoyield caused by fatigue is thus determined by work function and valence band changes.
Surface Science 99 (1980) 384-391 © North-Holland Publishing Company THEORETICAL DETERMINATION OF THE STRUCTURE OF ACETYLENE O N P t ( l 11) A l f r e d B. A N D E R S O N
Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA and