Temperature dependence of photoelectron scattering from a monolayer

The lattice stiffening transition in UO2 single crystals

The effective Debye temperatures ([Formula: see text]) of the surface region of UO₂ single crystals, prepared by the hydrothermal synthesis technique, were obtained from temperature-dependent x-ray photoemission in the temperature range of 300 K-623 K. A lattice stiffening transition, characterized by different regions of different effective Debye temperature, 500  ±  59 K below 475 K and 165  ±  21 K above 475 K is identified. A comparison of the temperature dependence of the effective UO₂ Debye temperature, with the changes in the lattice expansion coefficient for UO₂, support strong lattice-phonon interaction arising from the Jahn-Teller distortion.

The surface relaxation and band structure of Mo(112)

The experimental and theoretical surface band structures of Mo(112) are compared. This surface band structure mapping is presented with corrections included for the lattice relaxation of the Mo(112) surface. Quantitative low energy electron diffraction (LEED) has been used to determine the details of the Mo(112) surface structure. The first layer contraction is 14.9% by LEED intensity versus voltage analysis and is in general agreement with the 17.6% contraction found from total surface energy optimization. The electronic band structure is mapped out along [Formula: see text]-[Formula: see text] and [Formula: see text]-[Formula: see text] of the surface Brillouin zone (SBZ). There is strong evidence of electron-phonon coupling particularly in the region of the Fermi level band crossing at 0.54 Å(-1).

Abnormal Temperature Dependence of Photoemission Intensity Mediated by Thermally Driven Reorientation of a Monomolecular Film

The photoemission intensities of organic molecular layers generally obey the Debye-Waller temperature dependence but not always. With the example of a monomolecular film formed from [1,1';4',1''-terphenyl]-4,4''-dimethanethiol, we show that pronounced deviations from Debye-Waller temperature behavior are possible and are likely caused by temperature-dependent changes in molecular orientation.