Anomalies of screening in d and f electron systems

A brief review is given of correlation effects in transition metals, their alloys, and compounds related to the dynamic nature of screening electron-e lectron interaction, especially in the presence of "soft" electron-hole exc itations (screening anomalies). The problem is considered concerning the in fluence of correlation effects on the electron energy spectrum features and electronic topological transitions in metals. Calculation results are give n that illustrate the importance of these effects in some systems (high-tem perature superconductors, mixed-valence systems, iron-group metals).