Temperature dependence of normal-emission photoelectron diffraction and analogies with extended x-ray-absorption fine structure

Journal Article · Thu Jan 15 00:00:00 EST 1981 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.23.493· OSTI ID:6686580

Kevan, S D; Tobin, J G; Rosenblatt, D H; Davis, R F; Shirley, D A

The temperature dependence of normal-emission photoelectron diffraction (NPD) of the prototype adsorbate-substrate system Se--Ni (001) was studied. Two interesting observations emerged. Thermal diffuse scattering yielded a decreasing peak-to-valley contrast ratio in NPD with increasing temperature characterized by an effective temperature THETA/sub eff/approx.135 K. Also, a new low-temperature form of p(2 x 2) selenium structure was observed, with d/sub perpendicular/ estimated to be larger by approx.(0.06--0.1) A than the room-temperature form. The new form, which is probably undissociated H/sub 2/Se, is apparent through a systematic NPD peak shift reminiscent of extended x-ray-absorption fine structure (EXAFS) spectra. It is noted that NPD, though usually associated with low-energy-electron diffraction, in fact has strong similarities to EXAFS. This is particularly evident in the importance of an extended k-space data set and in the temperature sensitivity.

• Research Organization: Materials and Molecular Research Division, Lawrence Berkeley Laboratory, Berkeley, California 94720
• OSTI ID: 6686580
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 23:2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
SELENIUM
CRYSTAL STRUCTURE
PHOTOELECTRON SPECTROSCOPY
ELECTRON DIFFRACTION
LATTICE PARAMETERS
TEMPERATURE DEPENDENCE
FILMS
NICKEL
SUBSTRATES
COHERENT SCATTERING
DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTS
METALS
SCATTERING
SEMIMETALS
SPECTROSCOPY
TRANSITION ELEMENTS
360104* - Metals & Alloys- Physical Properties