First study of single-neutron excitations of $^{\mathrm{207}}$Hg via the $^{\mathrm{206}}$Hg(d,p) reaction*

We report the first exploration of the single-neutron shell structure of $^{\mathrm{207}}$Hg, which located below Z $=$ 82 and with N \textgreater 126 in an almost unexplored region of the nuclear chart. The $^{\mathrm{206}}$Hg(d,p) neutron-adding reaction in inverse kinematics at 7.4 MeV/u was performed at CERN's HIE-ISOLDE facility. The single-neutron excitations in $^{\mathrm{207}}$Hg were determined from the scattered protons, which were detected using the new ISOLDE Solenoidal Spectrometer at a magnetic field strength of 2.5 T. The Q-value resolution was 140 keV FWHM. Angular distributions suggest that the 0g$_{\mathrm{9/2}}$, 2d$_{\mathrm{5/2}}$, 3s$_{\mathrm{1/2}}$, 2d$_{\mathrm{3/2}}$ and 0g$_{\mathrm{7/2}}$ states were observed. An extrapolation of the single-particle energies using $^{\mathrm{209}}$Pb and $^{\mathrm{207}}$Hg as anchors towards the neutron threshold plays an important role in improving our understanding the r-process nucleosynthesis in this region.