On wave theory of the photoeffect

The photoelectric effect has been discovered by H. Hertz, and studied experimentally by P. Lenard. First theoretical explanation has been done by A. Einstein who suggested the corpuscular theory of light introducing the "photons" which are particles of the light. In the framework of the Schr\"odinger theory the effect has been described first by G. Wentzel who calculated the angulardistribution of the photocurrent. The calculation relies on the perturbation procedure applied to the coupled Maxwell-Schr\"odinger equations.