Abstract
Angle-resolved photoemission extended fine structure (ARPEFS) was used to determine the structure of c(2x2)P/Fe(100). P 1s core-level photoemission data were collected normal to the (100) surface and 45(degree) off-normal along the (011) direction at room temperature. Close analysis of the auto- regressive linear prediction based Fourier transform and multiple- scattering spherical-wave calculations indicate that the P atoms adsorb in the high-coordination fourfold hollow sites. The P atoms bond 1.02 (angstrom) above the first layer of Fe atoms and the Fe-P-Fe bond angle is 140.6 deg. It was also determined that there is no expansion of the Fe surface. Self-consistent-field X(alpha) scattered wave calculations were performed for the c(2x2)P/Fe(100) and the c(2x2)S/Fe(100) systems. These independent results are in excellent agreement with this P/Fe structure and the S/Fe structure previously published, confirming the ARPEFS determination that the Fe(sub 1)-Fe(sub 2) interlayer spacing is contracted from the bulk value for S/Fe but not for P/Fe. (DOE)