------------------------------------------------------------ RECORD NO.: 4675247 INSPEC Abstract No: A9413-2160G-001 AUTHOR: Rae, W.D.M.; Zhang, J. CORP SOURCE: Nucl. Phys. Lab., Oxford Univ., UK TITLE: Triangular alpha cluster geometries and harmonic oscillator shell structure SOURCE: Modern Physics Letters A, vol.9, no.7, p. 599-607 ISSN: 0217-7323 CODEN: MPLAEQ PLACE OF PUBL: Singapore LANGUAGE: English YEAR: 7 March 1994 TREATMENT: T Theoretical or Mathematical ABSTRACT: We demonstrate that there is a link between the underlying geometrical structure in the Bloch-Brink alpha -cluster model and shell structure in the axially-symmetric deformed harmonic oscillator model. Indeed all the axially-symmetric harmonic oscillator configurations can be related to structures formed from triangular layers of alpha -clusters whose centres lie on an FCC lattice. In particular all harmonic oscillator closed-shell nuclei can be related to tetrahedral arrangements of alpha -cluster centers, generalizing the result known for /sup 16/O for many years. These results suggest that the octupole degree of freedom which can be associated with triangular and tetrahedral alpha -cluster structures could be important in such nuclei (29 Refs.) DESCRIPTORS: harmonic oscillators; nuclear cluster model; nuclear shape; nuclear shell model; nuclei with mass number 6 to 19 IDENTIFIERS: triangular alpha cluster geometries; harmonic oscillator shell structure; geometrical structure; Bloch-Brink alpha - cluster model; axially-symmetric deformed harmonic oscillator; FCC lattice; closed-shell nuclei; tetrahedral arrangements; /sup 16/O; octupole degree of freedom CLASS CODES: A2160G (Cluster models); A2160C (Shell model); A2110F (Shape, charge, radius, form factors and structure functions)A2720 (6