Shell model and collective high spin states in nuclei: 45,47Ti, 47,49V and 51Mn

Several new levels, in particular with high angular momentum, were observed in the odd-A nuclei of the 1f 7 2 shell 45,47Ti, 47,49V and 51Mn. Several reactions mainly induced by heavy ions were studied: 40Ca(14N, 2pn)51Mn, 50Cr(3He, pn)51Mn, 35Cl(16O, αpn)45Ti, 27Al(24Mg, αpn)45Ti, 44Ca(7Li,p3n)47Ti, 24Mg(32s, α3p)49V, 40Ca(12C, 3p)49V and 24Mg(32S, 2αp)47V with bombarding energies from the Coulomb barrier value up to the maximum corresponding to ≈ 9.5 MV Tandem voltage. Standard techniques of in-beam γ-ray spectroscopy were adopted: γ-ray excitation functions, angular distributions and γ-γ coincidences. Methods of spin assignment are discussed. The following new levels (energies in keV) were observed or confirmed (labelled with c):51Mn: 1139, 9 2-c; 1488, 11 2-c; 2957, 13 2-; 3250, 15 2-; 3679, 17 2-; 4138, 19 2-; 5637, 21 2-, 6468, 23 2-; 7172, ( 27 2)- 45Ti: 2656, 13 2(-); 3016, 15 2(-); 3601, 17 2(-), 5421, ( 21 2-); 6164, ( 23 2-); 7145, ( 27 2-). 47Ti: 4498, 19 2-. 47V: 2615, ( 15 2-), 4143, ( 19 2-); 5907, ( 23 2-). 49V: 3324, 17 2-, 3741, 19 2-. The nature of these nuclei seems complex. Many high spin states are understood in the frame of the pure (1f 7 2)n shell model. But several discrepancies in its predictions, particularly for the low spin states, require a larger configuration space and/or the introduction of a collective model. © 1978.