The first excited states of 9 Be and 9 B

It is found here that the 1/2 + first excited state of 9 Be 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 9 B 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− 8 Be phase shift. The phase shifts are obtained from N − 8 Be effective potentials deduced from the data on the photodisintegration of 9 Be. 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.