Particle capture cross sections for a Reissner--Nordström black hole

Expressions are derived for the capture cross sections of photons (or uncharged ultrarelativistic particles) and of uncharged particles that are slowly moving at infinity by a spherically symmetric, charged black hole. The well known expressions for the photon capture cross sections and for capture cross sections of slowly moving particles in the Schwarzschild metric and extreme Reissner--Nordström metric are obtained by taking the appropriate limits in the equations derived.