Proton Hole Response Function on /sup 196/Pt and /sup 197/Au Transitional Target Nuclei Up to High Excitation Energy

摘要

The proton hole response functions have been studied on the transitional target nuclei /sup 196/Pt and /sup 197/Au via the (d, /sup 3/He) reaction at E/sub d/ = 108.4 MeV, up to 6 MeV and 18.5 MeV excitation energy respectively. /sup 196/Pt low lying levels have been studied in addition at E/sub d/ = 50 MeV. Spectroscopic information gained on the low lying levels in the /sup 195/Ir and /sup 196/Pt residual nuclei allows the discussion of the 3s/sub 1/2/ and 2d/sub 3/2/ orbital filling. For both /sup 195/Ir and /sup 196/Pt, new 2d/sub 5/2/ and 1h/sub 11/2/ levels or groups are observed. The /sup 196/Pt spectra exhibit a broad bump between 6 and 15 MeV excitation energy riding over a continuous background. The study of the excitation energy spectra up to 27 MeV leads to a consistent subtraction of the background. The contributions of the 1g/sub 9/2/, 2p and 1f inner hole strengths are deduced by least square fits of DWBA angular distributions. About the whole 1g/sub 9/2/ and 2p inner hole strengths and 50% of the 1f strengths are found below E/sub x/ = 18.5 MeV. The background correction is also used to reanalyse previous data obtained via the same reaction on the spherical /sup 208/Pb target for comparison. Experimental results on centroid separation energies are compared with Hartree Fock predictions. The spreading widths and specific features of the strength distribution shapes in /sup 195/Ir and /sup 196/Pt and /sup 207/Tl are discussed in connection with the dominant quadrupole collective degrees of freedom of the two first nuclei contrasting with the strong vibrational modes in /sup 207/Tl. The valence hole fragmentation in /sup 195/Ir is described in the framework of the Core-Quasi-Particle-Coupling-Model. (ERA citation 13:002391)