Abstract.
It is found here that the 1/2+ first excited state of 9Be is a virtual state with the energy of −23.5 KeV. The line shape for the excitation of the state is approximated with a simple analytic form based on the effective range expansion. The partner in 9B of this state is found to be a resonance with a maximum in the peak at about 1.1 MeV, FWHM of 1.5 MeV, and complex energy of 0.6 −i0.75 MeV. The line shape for its excitation is calculated in terms of the p−8Be phase shift. The phase shifts are obtained from N−8Be effective potentials deduced from the data on the photodisintegration of 9Be. A possibility for direct extraction of the energy of the resonant state from experimental data is also discussed, and an expression for a residue at a virtual state pole in terms of a quadrature taken over the virtual state eigenfunction is given.
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Received: 23 March 1998 / Revised version: 3 September 1998
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Efros, V., Bang, J. The first excited states of 9Be and 9B . EPJ A 4, 33–39 (1999). https://doi.org/10.1007/s100500050201
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DOI: https://doi.org/10.1007/s100500050201