Abstract
We searched for laser-induced 2-2 transitions in ( ions at low pressure (4.1 kPa), where we determined a 2S lifetime of 1.014±0.121 μs from the simultaneously measured 2S→1S two-photon transitions. In contrast to a similar experiment in He gas of 40 bar (4× Pa) reported by Carboni et al. [Nucl. Phys. A278, 381 (1977)], which was based on the questionable metastability of the 2S state at that pressure, we found no resonance effect at the wavelength λ=811.7 nm. We can reject this wavelength with a confidence level of less than 2×, and the interval 811.4≤λ≤812.0 nm with a greater than 95% probability.
- Received 23 March 1992
DOI:https://doi.org/10.1103/PhysRevA.46.2363
©1992 American Physical Society