THE 1ST EXCITED-STATE OF BE-8 STUDIED IN THE LI-7(P,GAMMA)BE-8 REACTION

In order to study the intrinsic line shape of the broad first excited 2+ state of 8Be, the radiative capture reaction 7Li(p,γ)8Be has been investigated in an energy range close to the center of the giant dipole resonance built upon this state. A large NaI(Tl) spectrometer with a well-known response function is employed. The data are fitted with spectral density functions derived from αα phase shifts in the framework of the R- matrix theory. The optimum value of the channel radius obtained from the fits, a = 4.5 fm, is in agreement with the value deduced from a similar analysis of a kinematically complete coincidence study of the 9Be(d,tα)4He reaction. The calculated spectral density function for a = 4.5 fm reaches its maximum at Ex = 2.91 MeV, the width (FWHM) is 1.23 MeV. © 1990.