Deformed states of high spin in42Ca

Abstract

Abstract. The 42Ca levels at 4,715 and 6,633 keV excitation energy have been investigated using the 39K(~, py) reaction at E~--14 and 15 MeV. From particle-7-ray angular correlations the spin assignments J(4,715)--6, 4 and J(6,633)= 8, 6, 4 have been obtained. Lifetime measurements using the Doppler-shift attenuation method yielded ~(4,715)= 120_+46 fs and z (6,633)= 52_ 21 fs. Both levels have positive parity and decay by enhanced E 2 transitions. They are interpreted as the J~= 6 + and 8 + members, respectively, of the K ~ =0-:-rotational band which has the E x--1,837, 2,423 and 3,250 keV states as further members.

Density of high-spin states in38Ar and42Ca

“…Hence the importance of threeparticle excitations becomes clear though we cannot identify specific levels as belonging to this configuration. The lowest lying J~= 6 + level of ~2Ca (apart from the 3,190keV level, which belongs to the f7~2 configuration) has been observed at 4,715keV excitation energy, the lowest J~=8 § level at 6,633keV [8]. These levels are deformed and members of a K~=0 + rotational band.…”

Quadrupole collectivity in Ca42 from low-energy Coulomb excitation with AGATA

“…The lifetime of the 6 + 2 state at 4715 keV was determined in a DSAM measurement [71] to be equal to 120(46) fs. The same technique was used to measure the lifetime of the 2 + 3 state at 3392 keV equal to 0.17(3) ps [80].…”

Coexistence of various deformed states and ± clustering in 42Ca

“…In 42 Ca, deformed states with mp-mh configurations and clustering behavior have been observed experimentally, and the rotational band built on the J π = 0 + 2 (1.84 MeV) state (K π = 0 + 2 band) has been observed [1,9]. This rotational band has a large moment of inertia that is similar to the ones of the SD bands in 36 Ar and 40 Ca, scaled by A 5/3 [9], which is proportional to square of quadrupole deformation parameter β in the liquid-drop model.…”

“…In the mass number region A ∼ 40, low-lying normal-deformed (ND) and superdeformed (SD) bands with many-particle-many-hole (mp-mh) configurations have been confirmed experimentally in 36,38,40 Ar [4,12,15], 40 Ca [5], 42 Ca [1,9], and 44 Ti [11]. The SD band in 36 Ar, ND and SD bands in 40 Ca, and SD band in 44 Ti are considered to have configurations of 4p8h, 4p4h, 8p8h, and 8p4h, respectively, relative to the sd-shell doubleclosed structure.…”