Particle spectrum of the Reissner-Nordstr\"om black hole

The Reissner-Nordstr"om black hole - moving mirror correspondence is solved. The beta coefficients reveal that charge makes a black hole radiate fewer particles (neutral massless scalars) per frequency. An old Reissner-Nordstr"om black hole emits particles in an explicit Planck distribution with temperature corresponding to the surface gravity of its outer horizon.