Effect of Exchange on L to K Capture Ratios

Two years ago, Robinson and Fink (1) called attention to a systematic discrepancy between observed and predicted L to K electron capture ratios. Many experiments have since been performed to investigate this discrepancy. The observed L to K ratio has been found (2-5) to exceed 5 to 25 percent the predicted L to K ratio for all nine of the precisely measured allowed electron captures with Z between 18 and 36. The calculations reported in this note remove the systematic disagreement between theory and experiment by including atomic states in the description of the radioactive system.