Pergamon zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA frog. Part Nucl. Phys., Vol. 38, pp. 137-146. 1997 0 1997 Elsevier Science Lid Printed in Great Britain. All rights reserved 0146-6410/97 $32.00 + 0.00 SOl46-6410(97)00018-S zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPON Relativistic Description of High Spin States P. RING and A. V. AFANASJEV Physik-Department der Technischen Universirtit M iinchen, D-85748 Garching, Germany Abstract Cranked Relativistic zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Mean Field Theory with a non-linear coupling of the u-meson field is used for a microscopic description of rotational bands in superdeformed nuclei. I systematic investigations of all measured yrast superdeformed bands in the .A = 140 ~ 150 mass region is presented. The agreement with experimental data is excellent. 1 Introduction. Since the discovery of the first discret.e superdeformed rotational hand (SD band) in the nucleus “*Dy [l] in 19S6, the investigation of superdeformation at high angular moments remains one of the most interesting and challenging topics of nuclear structure. The detailed experimental investigation of superdeformation relreals many interesting properties of superdeformed bands like the phenomenon of identical bands (see for example Ref. [2]) and suggested manifestation of &-symmetry (see [3] and references therein). By now, it is commonly accepted that the detailed properties of the SD bands like the dependence of the dynamic moment of inertia .J(*) on the rotational frequency and the absolute values of charge quadrupole moments Qo depend sensitively on the nunlber of occupied high-Y intruder orbit&. This feature of the SD bands was investigated in detail for the first time in Ref. [4] using the Cranked Silsson (CX) approach. Later, it was confirmed within the Cranked IIbods-Saxon (CWS) approach [5]. Systematic investigations of superdeformed rotational bands in different mass regions have so far been performed only within the CWS or CN approaches (see, for example, Refs. [6, 7, 5, 8, 91). Moreover, many experimental manuscripts contain applications of these models to the latest experimental data. These investigations are based on a semi-phenomenological approach and contain many parameters describing the underlying liquid drop as well as the single particle shell model. By treating the bulk and the single particle properties separately they have the advantage to fit many details of the actual nuclei under investigations directly to the appropriate region under investigation. The rich variety of physical phenomena in the region of superdeformed shapes is based on a complicated and rather subtle 137