The two-photon approximation for the four-photon decay of the 4d excited state in hydrogen

摘要

Abstract: The method of two-photon approximation for multiphoton decay is applied to the decay of the 4d state in thenhydrogen atom. In the process of four-photon decay the two-photon contribution that leads to radiation escape, from theninteraction with matter, is considered. This may be helpful for a strict description of the recombination process in the hy-ndrogen atom and, in principle, for the history of hydrogen recombination in the early universe.