APPROXIMATE METHOD FOR REDUCING THE EFFECT OF BEAM MISALIGNMENT ON LOW-ENERGY-ELECTRON DIFFRACTION I(E) CURVES AT THE NORMAL INCIDENCE - THE HORIZONTAL-BEAM METHOD

An approximate method is proposed for the measurement of intensity-ene rgy [I(E)] curves of low-energy electron diffraction at the normal inc ident condition. In this method only two equivalent spots located in t he horizontal direction are optimized to have identical I(E) curves. I t is found that I(E) curves obtained by this method approximate well t hose at the exactly normal incident condition, as long as the total mi salignment is less than 1-degrees. The reason for the success of this method is discussed. Advantages and disadvantages of this method are p resented. It is emphasized that reproducible I(E) curves can be obtain ed easily due to a clear guideline of this method.