Revision of the energy scheme of the arsenic atom

Abstract A fine structure analysis for the system Σ 7 n ′= 5 4 s 2 4 p 2 n ′ s + Σ 5 n ′= 4 4 s 2 4 p 2 n ″ d + 4 s 4 p 4 in the spectrum of neutral arsenic is performed on the basis of available experimental data. This work has proved, that the levels of the 4s4p 4 configuration are at positions very different from those given in the literature so far. Besides it is shown that the 4s4p 4 configuration strongly influences the even level system of As I. The spectroscopic assignments of the even parity electronic levels are given on the basis of the theoretical results. The quantum numbers n ′ and l ′ for excited electron states fail to be good quantum numbers in many cases.