Forbidden transitions in the helium atom - art. no. 042510

Nonrelativistically forbidden, single-photon transition rates between low-l ying states of the helium atom are rigorously derived within quantum electr odynamics theory. Equivalence of velocity and length gauges, including rela tivistic corrections is explicitly demonstrated. Numerical calculations of matrix elements are performed with the use of high-precision variational wa ve functions and compared to former results.