Lifetimes of low-lying states in ¹⁹F

Lifetimes of low-lying states in ¹⁹F were measured using the Doppler-shift attenuation method through the ¹⁵N(α, γ)¹⁹F reaction. Values of τ_m = 3700 ± 700 fs (1.35 MeV), 140 ± 15 (1.46), 19 ± 7 (4.00) and 63 ± 19 (4.03) were obtained for the lowest 5 2^-, 3 2^-, 7 2^- and 9 2^- members, respectively, of the K^π = 1 2^- rotational band and 5 ± 3 fs (1.55 MeV) and 370 ± 25 (2.78) for the 3 2⁺ and 9 2⁺ members of the K^π = 1 2⁺ ground-state band. For the Doppler-shift attenuation analysis correction factors of the nuclear and electronic stopping powers were determined by measuring the Doppler-shift attenuation and γ-ray line shape of the 2.78 → 0.20 MeV transition and range values of 100, 200. 300 and 370 keV ¹⁹F nuclei in tantalum. All calculations were done with Monte Carlo methods. The transition strengths are discussed in terms of different theoretical predictions.