ABSORPTION CROSS-SECTION OF REISSNER–NORDSTROM AND SCHWARZSCHILD–DE SITTER EXTREMAL BLACK HOLE.

The nature of scalar wave functions near the horizon of Reissner–Nordstrom (RN) extremal and Schwarzschild–de Sitter (SdS) extremal black holes are found using WKB approximation and the effect of reflection of waves from the horizon. The absorption cross-section σ_abs when RN extremal and SdS extremal black holes placed in a Klein–Gordon field is calculated. [ABSTRACT FROM AUTHOR]