TY - JOUR
T1 - Energy dependence of diffractive and inelastic scattering of He and H2 from MgO(100)
AU - Kolodney, Eliezer
AU - Amirav, Aviv
N1 - Funding Information:
We would like to thank R.B. Gerber for stimulatingd iscussionsa nd C. Horowitz for skillful technicala ssistanceT. his work was supportedb y the PetroleumR esearchF und, administeredb y the American Chemical Society, and the United States-IsraelB inational ScienceF oundation Grant No. 3209.
PY - 1985/6/2
Y1 - 1985/6/2
N2 - The energy dependence of both the diffractive and inelastic scattering of He and H2 from single crystal MgO(001) was studied using a heated supersonic nozzle source. A large anisotropy of helium inelastic scattering from MgO was found for the two azimuths studied, namely the 〈100〉 and 〈110〉. Helium scattering in the 〈110〉 azimuth resulted in a large amount of inelasticity which revealed pronounced maxima in its energy dependence near 150 meV helium kinetic energy. In the 〈100〉 azimuth the degree of inelasticity was relatively energy independent. The specular reflection in the 〈100〉 azimuth showed a dramatic decrease with energy in a smooth and structureless way over almost three orders of magnitude. This behavior was well fit by the hard corrugated surface (HCS) theory, yielding a corrugation amplitude of 0.16 Å. The scattering at helium kinetic energies above 150 eV is completely dominated by the first order diffraction peaks and somewhat by second order. In contrast to helium scattering, hydrogen scattering is not anisotropic or azimuth dependent and also does not show a qualitative change in our range of kinetic energies, being dominated by the specular reflection at all energies. A fit of this specular intensity by the HCS theory resulted in an upper limit of 0.11 Å corrugation amplitude for hydrogen, which is considerably lower than for helium.
AB - The energy dependence of both the diffractive and inelastic scattering of He and H2 from single crystal MgO(001) was studied using a heated supersonic nozzle source. A large anisotropy of helium inelastic scattering from MgO was found for the two azimuths studied, namely the 〈100〉 and 〈110〉. Helium scattering in the 〈110〉 azimuth resulted in a large amount of inelasticity which revealed pronounced maxima in its energy dependence near 150 meV helium kinetic energy. In the 〈100〉 azimuth the degree of inelasticity was relatively energy independent. The specular reflection in the 〈100〉 azimuth showed a dramatic decrease with energy in a smooth and structureless way over almost three orders of magnitude. This behavior was well fit by the hard corrugated surface (HCS) theory, yielding a corrugation amplitude of 0.16 Å. The scattering at helium kinetic energies above 150 eV is completely dominated by the first order diffraction peaks and somewhat by second order. In contrast to helium scattering, hydrogen scattering is not anisotropic or azimuth dependent and also does not show a qualitative change in our range of kinetic energies, being dominated by the specular reflection at all energies. A fit of this specular intensity by the HCS theory resulted in an upper limit of 0.11 Å corrugation amplitude for hydrogen, which is considerably lower than for helium.
UR - http://www.scopus.com/inward/record.url?scp=0000262815&partnerID=8YFLogxK
U2 - 10.1016/0039-6028(85)90024-X
DO - 10.1016/0039-6028(85)90024-X
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AN - SCOPUS:0000262815
SN - 0039-6028
VL - 155
SP - 715
EP - 731
JO - Surface Science
JF - Surface Science
IS - 2-3
ER -