10 20 30 40 50  (fm) -2 -1 0 1 2 3 V eff ( ) (MeV) $^{9}$Be effective potentials $^{9}$B effective potentials 10 20 30 -3 0 3 $^{9}$Be: V$_{eff}$ $^{9}$Be: V$_{eff}$  Q$_{11}$ 0 25 50 75  (fm) 0 0.2 0.4 0.6 0.8 1 Partial wave content l$_{x}$=l$_{y}$=0, L=0 l$_{x}$=l$_{y}$=1, L=0 l$_{x}$=l$_{y}$=2, L=0 l$_{x}$=l$_{y}$=3, L=0 Thick curves: $^{9}$Be Thin curves: $^{9}$B N x y FIG. 3: The partial wave decomposition of the lowest adia- batic angular wave function for $^{9}$Be (thick) and $^{9}$B (thin) as function of hyperradius ρ . The partial angular momenta l x and l y correspond to the coordinates indicated in the figure. For l x = l y = 2 and l x = l y = 3 the curves for $^{9}$Be and $^{9}$B can not be distinguished. FIG. 2: Lowest adiabatic potentials for $^{9}$Be and $^{9}$B as a func- tion of the hyperradius. The inset shows the $^{9}$Be lowest po- tential with and without the rearrangement coupling term Q . consistent with photodissociation cross section measure- ments and the entangled R -matrix analysis of an a priory assumed resonance [11]. The fitting parameters are posi- tion and energy dependent width of a two-body neutron- $^{8}$Be resonance of s -wave character. Several years prior to this analysis it was suggested that the state should be understood as a virtual state and the photodissociation cross section correspondingly analyzed [9]. However, this does not reproduce the measurements in [11]. An attractive pocket and a constant large distance po- tential without any barrier in the transition region is not able to support a resonance of finite width at energies above the large distance asymptotic value. However, in- clusion of the coupling term Q (see Eq.(1)), provides an otherwise totally absent barrier as seen in the inset of Fig.2. This all decisive barrier then arises from a strong ρ dependence of the intrinsic (angular) wave function φ , as seen from the definition in Eq.(2). Three-body results for $^{9}$Be( 1 / 2 $^{+}$). The shortcomings of many previous methods are the initial assumption of two-body character of this structure. Since the final de- cay products are three particles we proceed to treat the system as a three-body system. We use the well estab- lished nucleon-nucleon and α -nucleon interactions from [18, 19]. The three-body restructuring can be seen from Fig.3 where the small distance structure of ρ less than 9 fm is p -waves between neutron and α -particles. This is due to the p$_{3}$$_{/}$$_{2}$ -resonance which provides the main part of the attraction. As ρ increases above 10 fm this partial wave is rapidly substituted by s -waves which are energetically more advantageous at larger distance where the attrac- tion vanishes and the centrifugal barrier dominates. At much larger distances an increasing number of partial waves contribute corresponding to the neutron far away from the two-body system of two α -particles in the spa- tially much smaller s -wave resonance, i.e. $^{8}$Be in the ground state. The combined result of the lowest adiabatic poten- tial and the diagonal coupling is able to support a res- onance. We compute the energy and width numeri- cally as the S -matrix pole found by complex scaling [20]. By adding a structureless short-range potential ( V 3 b = V 0 exp( − ρ $^{2}$/ρ2$_{0}$), with ρ 0 = 5 fm), which con- tributes only in the pocket region, we can move the res- onance energy by modifying the V 0 strength but without disturbing the resonance structure. This is useful both The adiabatic potentials produced through the adia- batic hyperspherical expansion method for these quan- tum numbers are shown in Fig.2. The higher ones show pronounced peaks at about 15–18 fm. The origin of the peaks is in the crossing between different angular eigen- values. In particular, the Q -functions in the effective potentials, (see Eqs.(1) and (2)), are responsible for the behaviour shown in the figure in the vicinity of the cross- ings. These couplings involve second derivatives of the adiabatic eigenfunctions, and they therefore reflect re- structuring of these functions. The lowest potential has a dominating attractive pocket at small distance. After hyperradii ρ larger than 12 − 14 fm the potential stabi- lizes at the resonance energy of 0 . 091 keV for the $^{8}$Be ground state. This stable region continues until inter- rupted by the crossings with the (infinitely many) higher potentials. The first of these crossings occurs at about ρ = 130 fm. 3