Abstract
In this work we investigate fluorescence decay of low-lying resonances with odd parity and total angular momentum below the threshold of helium. After discussing the photoabsorption cross section for creation of such states, we estimate the probability for the primary fluorescence transition to states below the first ionization threshold. The subsequent fluorescence cascade decay brings helium into the ground state or into one of the two long lived states. We discuss the time scale of the cascade and combine all the calculated transition probabilities to determine branching ratios for singlet and triplet metastable production. Finally, we estimate the angular distribution of the emitted uv photons and perform a comparison with the recent experimental data of Penent et al. [Phys. Rev. Lett. 86, 2758 (2001)].
- Received 16 May 2001
DOI:https://doi.org/10.1103/PhysRevA.65.032520
©2002 American Physical Society