On the shape and fine structure of the K absorption discontinuity of cobalt in the metal and in its compounds, PrCo5 and SmCo5

The shape and the extended fine structure (EFS) of the X-ray K absorption discontinuity of cobalt have been studied in the pure metal and in two of its compounds, namely, PrCo5 and SmCo5. The main absorption discontinuity is found to split into two components for cobalt metal and the compounds. The shapes of the discontinuities have been interpreted in the light of the bidirectional orbital approximation (BOA). The absorption maxima in the EFS have been explained on the basis of Lytle's theory. The average bond lengths for the systems have been determined from the fine structure employing Levy's method. (author)