Shell-model calculations on odd-parity levels of nuclei in the range 33S−41Ca

Abstract

The shell model is used to investigate quantltahvely some odd-parity levels of nuclei m the range z~S-41Ca An inert z°-S core Is assumed w~th a residual two-particle interaction of the outer nucleons. Only one nucleon ~s considered to be in the lfff shell, while the others are m "the ld k shell. The interaction matrix elements are reduced to hnear expressions m 14 parameters (i e 12 two-particle interactions and two binding energies to the core)The numerical results are presented as they are obtained from fitting the 14 parameters to 60 nuclear level energies. From the values of these parameters the energies and spins of about 240 levels are derived. Though the root mean square dewat~on of the calculated energies from the experimental energies is about 0.5 MeV, most of the level orders are calculated correctly. In addthon, the energies of some 0 + levels are calculated from configurations containing two particles in the lf.~ shell. These level energies appear to have a larger spread around the experimental energies An expansion of the matrix elements of the effective interaction of one nucleon m the ldff and one m the lf~r shell m terms of lnteract~on moments shows that the mean two-body rateraction for the T = 0 case is attractive, with a significant quadrupole sphttmg; this agrees with a weak spin dependence of the effective nuclear forces. The mean two-body interaction for the T = 1 case is shghtly repulsive, the octupole sphttmg being the most significant one

Excited States in37Ar from the34S(α,nγ)37Ar Reaction

“…Furthermore a state at 3 516 keV, which we do not observe is known to have JS=3/2-. A shell model calculation on the odd parity levels in 37Ar has been made by Erne [18], who assumed an inert 32S core. The outer nucleons were considered to be in the 1d3#% and lf,,* shells, with the restriction that only one nucleon was allowed to be in the lf,/2 orbit.…”

Advances in Nuclear Physics, Volume 27

“…The comparison of these with matrix elements determined from experiment by Erne (1966) was even more impressive. The comparison of these with matrix elements determined from experiment by Erne (1966) was even more impressive.…”

Plasma-Induced Deterioration of Mechanical Characteristics of Microcantilever

“…Recent measurements in the upper region of the s -d shell have shown that the high-spin negative-parity states in "Si can be well represented by the simple rotational model (Viggars et a1 1973), while in 37Ar they can be explained by the core-excitation model (Gadeken et a1 1974). The high-spin negativeparity states in 37Cl cannot however be explained by either of these models or the simple shell-model calculations available at present (eg Erne 1966).…”

“…The E3 strength of the ground-state transition is 13 & 1 Wu which is in good agreement with the 38Ar (3-+ 0') E3 transition strength of 16&6 Wu. Shell-model calculations using an inert ',S core have been performed by Erne (1966) and Maripuu and Hokken (1970). Ern6 allowed one particle to be excited into the If,,, orbital while the other calculation allowed one particle to be excited into either the If,,, or the 2p3/, orbital.…”