Structure analysis of Si(111)2©1 with low-energy electron diffraction

A structure analysis of the Si(111)2©1 surface is performed using extensive new low-energy electron-diffraction data (12 beams). Although the $\pi$-bonded chain model in its original form shows gross disagreement with low-energy electron diffraction, a modification of that structure gives moderate agreement. The major modifications are a buckling in the outer chain and an overall compression.