Investigation of196,198Pt and202,204Hg with the (d, pn?) reaction

Abstract

Gamma-ray and conversion electron spectra were measured in the reaction of 25 MeV deuterons on 174yb, 196'19apt, 2~176 and 132Th. The (d, pxn) deuteron break-up reactions were studied by the measurement of py-and 77-coincidences. Levels with spins up to approximately 10h are observed in the (d, pn) reactions, with a strong preference of the population of yrast states. In the Pt and Hg nuclei the ground bands are seen up to the 6 + states and in 196,198pt the semi-decoupled 5-, 7-, and 9-yrast levels are populated most strongly. In 2~176 we observe fairly strongly new levels with tentative assignments of 5-and 7-. In addition a number of previously unknown levels are identified in the Pt and Hg nuclei, for which no spin-parity assignments could be obtained. A discussion of the level structure in terms of the interacting boson model (196,198pt) and the shell model (/~176 is given.

Triaxiality and?-softness in196Pt

“…The transition which is expected to have the highest intensity, 3 + ~ 2] at 327 keV, could not be evaluated due to a contamination by the 2~--*0[ transition of 194pt at 328 keV. In the angle-integrated spectra we observe a line at EV=594 keV which has been seen by Schiller et al [27] in coincidence with the 3~ ~22+ transition and been suggested to be the 5[ ~ 3[ transition. We can support this assumption by qualitative arguments: the observed intensity agrees well with model predictions for the 51+ ~ 3[ transition, and the measured gamma multiplicity corresponds to the expected value.…”

“…Later, Schiller et al [27] suggested this state to be the expected 4~--level, because in a (d, pnv) experiment a transition of 521 keV was observed in coincidence with the 31 + ~ 22+ transition which was assigned the 4~ ~ 3~ transition. We could not see this line because of the strong 4[ ~ 2~ transition of the same energy.…”

“…A partial level scheme, based on the data of the present study in combination with information published previously [17,18,26,27,29,33,38] is presented in Fig. 4.…”

“…Information on the level scheme of ~96pt was previously obtained from studies of the y radiation after /%decay [24,25], and from (p, p')- [26], and (d, pnT)-experiments [27]. In these investigations levels up to I ~ = 4 + were identified.…”

Investigation of203, 205Hg with the (d, p?) reaction ? Identification of thei 13/2 neutron hole state in205Hg

“…However, the 7-ray directly depopulating the isomeric level could not be identified, and Maier et al therefore suggest the existence of an unobserved low-energy 13/2 + ~ 9/2-M2 transition. In a previous investigation [2] we had found, that levels in 2~ are populated with appreciable cross section in the 2~ (d, p) deuteron break-up reaction. We have therefore carried out a more extended study of 2~ in this reaction, in order to identify the v i13/2 level.…”