Robert W. Zurmuhle

We are presently using heavy-ion reactions to study extremes of nuclear structure at very high angular momentum and excitation energy, as well as to examine mechanisms of nuclear reactions. Our major focus has been on resonances in heavy-ion systems. We have studied these systems primarily in elastic and inelastic scattering, and, in a few instances, in reactions leading to alpha- panicle transfer channels.

The formation of long-lived states in the composite system can be lied closely to grazing collisions between the interacting heavy ions. Such grazing trajectories are particularly selective as they are subjected to much less violent collisions than central orbits, and therefore have a much higher probabiliw for emerging in an exit channel rather similar to the entrance channel. They can form states of extremely high angular momentum. For example, in collisions between two "Mg nuclei, we have discovered a number of surprisingly narrow states at high [- 60 MeV] excitation energy in the composite nucleus "Cr. Nuclear model calculations suggest that these resonances have very high angular momentum and that they should preferably fission into equal mass fragments. The calculated shape of the rotating nucleus at the scission point closely resembles a coniiguration with two prolate deformed "Mg nuclei touching at their poles. A measurement of the angular momentum for one of these resonances yielded a value of 36 h in excellent agreement with results of the nuclear model calculations.

• Emeritus Professor Professor, University of Pennsylvania (1976-)
• Associate Professor, University of Pennsylvania (1967-76)
• Assistant Professor, University of Pennsylvania (1963-67)
• Research Associate, University of Pennsylvania (1961-63)

• "Correlated Intermediate Structures in the Elastic-Inelastic Scattering and a-Transfer Channels of "Mg + "Mg," S. Saini, R.R. Betts, R.W. Zurm6hle, P.H. Kutt, and B.K. Dichter, Phys. Lett. B 185, 316 (1987).
• "Single and Correlated Spin Alignments for Resonances in "Mg + 14Mg Inelastic Scattering," A.H. Wuosmaa, R.W. Zurm6hie, P.H. Kutt, S.F. Pate, S. Saini, M.L. Halbert, and D.C. Hensley, Phys. Rev. Lett. 58, 1312 (1987).
• "Resonance Behavior in the 2IMg + "Si System," A.H. Wuosmaa, S. Saini, P.H. Kutt, S.F. Pate, R.W. Zurm6hle, and R.R. Betts, Phys. Rev. C, 36, 1011 (1987).
• "A UHV-Compatible AE-E Gas Telescope for Depth Probing and Surface Analysis of Light Elements," A.M. Behrooz, R.L. Headrick, L.E. Sieberling and R.W. Zurm6hle, Nucl. Inst. Methods B28, 108 (1987).
• "Properties of Intermediate Width Structure in IIC(12C 112C)12C(o -,+)," S.F. Pate, R.W. Zurm6hle, P.H. Kutt, and A.H. Wuosmaa. Phys. Rev. C 37, 1953 (1988).
• "Spins and Spin Alignment of Heavy Ion Resonances," R.W. Zurm6hle, Proc. Fifth Int. Conf. Clustering Aspects in Nucl. and Subnucl. Systems, Kyoto 1988, J. Phys. Soc. jpn, 58, Suppl. p.37 (1989).
• "Recent Studies of Heavy Ion Resonances at the University of Pennsylvania," R.W. Zurmbhle, Proc. of the JAERI International Symposium on Heavy-Ion Reaction Dynamics in the Tandem EnerAy Region, Hitachi, 1988 (Universal Academy Press, Tokyo, 1989), p. 169.
• "Reaction Mechanisms in "Si + "Mg -* a + "Mg + "Mg and a + I Ne + 18Si," A.H. Wuosamaa, S.F. Pate, and R.W. Zurmbhle, Phys. Rev. C, 40 173 (1989).