Surface Structure Analytical Method by Extended Appearance Potential Fine Structure

我们使用俄歇电子出现势（AEAPS）谱的测量系统测量EAPFS谱，因为两者都可以作为初级电子能量的函数获得。精细结构以二阶导数模式记录。个人计算机用于初始设置加速电压以及用于平均数据点的相加以提高信噪比。数据存储在软盘上。作为样品，使用多晶Cr、蒸镀Ti薄膜和非晶TiFe合金膜。1.多晶Cr：我们得到的最近邻原子间距分别为2.53（1=0）、2.54（1=1）和2.54（1=2）。这些值与体值（2.50A）很好地一致。蒸发的Ti薄膜：通过对阈值以上精细结构的分析，得到了最近邻原子间距分别为2.93（1=0）、2.93（1=1）和2.58（1=2）<L_2>。另一方面，从阈值以上的精细结构获得了3.29A（1=0）、3.29A（1=1）和2.97A（1=2）的结果<L_3>。当体Ti的最近邻原子间距为2.91时，可以认为在激发时发生了1=0和1=1的跃迁<L_1>。到1=2的跃迁在激发时是不稳定<L_3>的。非晶TiFe合金膜：通过对Ti阈值以上精细结构的分析，我们得到了最近邻原子间距分别为2.58（1=0）、2.44（1=1）和2.31（1=2），在<L_1>Ti阈值以上分别为2.87、2.77和2.57<L_3>。由于没有关于非晶态TiFe合金原子间距的数据，我们不能确定最终态的掺杂水平。但是，由于尽管化学环境不同，但可以假设末态的角动量分布相同，因此我们可以估计最近邻间距约为2.5埃。

We measured the EAPFS spectra using a measuring system of the Auger electron appearance potential(AEAPS) spectra, since both could be obtained as a function of the primary electron energy. The fine structure was recorded in the second-derivative mode. A personal computer was used for initially setting the accelarating voltage as well as for averaging the addition of data points in order to improve the signal-to-noise ratio. The data were stored on a floppy disk. As the samples, polycrystalline Cr, evaporated Ti thin film and amorphous TiFe alloy film were used. 1. Polycrystalline Cr: we obtained a nearest-neighbour atomic spacing of 2.53A(1=0), 2.54A(1=1) and 2.54A(1=2), respectively. These values are in good agreement with the bulk values(2.50A).2. Evaporated Ti thin film: we obtained a nearest-neighbour atomic spacing of 2.93A (1=0),2.93A(1=1) and 2.58A(1=2) by analyzing the fine structure above the <L_2> threshold. On the other hand, the results of 3.29A(1=0), 3.29A(1=1) and 2.97A(1=2) were obtained from the fine structure above the <L_3> threshold. As a nearest-neighbour atomic spacing of bulk Ti is 2.91A, it is considered that the trantition into 1=0 and 1=1 occure prominantly at the <L_1> excitation. The transition to 1=2 is prominant at the <L_3> excitation.3. Amorphous TiFe alloy film: we obtained a nearest-neighbour atomic spacing of 2.58A (1=0), 2.44A(1=1) and 2.31(1=2), respectively by analyzing the fine structure above the Ti- <L_1> threshold and obtained 2.87A, 2.77A and 2.57A above the Ti- <L_3> threshold. As there are no data about the atomic spacing of amorphous TiFe alloy, we can not decide the prominant level of the final state. But, as the same distribution angular momenta in the final state can be assumed in spite of the differing chemical environment, we can estimate a nearest-neighbour spacing of about 2.5A.