Fine structure in the  decay of Hg and Au

The $$ -decay fine structure of $$ Hg and $$ Au was studied by means of decay spectroscopy. Two experiments were performed at the Accelerator Laboratory of the University of Jyväskylä (JYFL), Finland, utilizing the recoil separator RITU and a digital data acquisition system. The heavy-ion induced fusion-evaporation reactions $$ Kr +  $$ Ru and $$ Kr +  $$ Mo were used to produce the $$ Hg and $$ Au nuclei, respectively. Studying the evaporation residues (ER, recoils)- $$ - $$ correlations and $$ - $$  coincidences, a new $$  decay with E $$  = 6156(10) keV was observed from $$ Hg. This decay populates the (9/2 $$ ) excited state at an excitation energy of 131.3(5) keV in $$ Pt. The internal conversion coefficient for the 131.3(5) keV transition de-exciting this state was measured for the first time. Regarding the $$ Au nucleus, a new $$  decay with E $$  = 5998(9) keV was observed to populate the 156.1(6) keV excited state in $$ Ir. Two de-excitation paths were observed from this excited state. Moreover, a new 215.7(13) keV transition was observed to depopulate the 424.4(13) keV excited state in $$ Ir. Properties of the $$ Hg and $$ Au $$  decays were examined in a framework of reduced widths and hindrance factors. For clarity and simplicity, the spin and parity assignments (e.g. $$ ) are presented without brackets throughout the text.