Abstract

A previous investigation of the $\ensuremath{\gamma}$-ray decay schemes of 7 resonances in the reaction ${\mathrm{Si}}^{29}(p, \ensuremath{\gamma}){\mathrm{P}}^{30}$ in the range ${E}_{p}=700\ensuremath{-}1750$ keV has been extended to 24 resonances in the range ${E}_{p}=300\ensuremath{-}1800$ keV. The new decay scheme studies were conducted with a 40-cc Ge(Li) detector. The spins, parities, isobaric spins, lifetimes, and transition multipolarity mixings for many resonances and bound states of ${\mathrm{P}}^{30}$ have been determined from an extensive series of angular-correlation, linear-polarization, and Doppler-shift-attenuation measurements. New resonance information includes the discovery that resonances previously reported at ${E}_{p}=1505, 1748, \mathrm{and} 1772$ keV are each doublets. The latter two have components at 1746 and 1749, and at 1773 and 1775 keV, respectively. The 1505-keV "resonance" was found to be a doublet with a separation of 0.7\ifmmode\pm\else\textpm\fi{}0.1 keV by means of high-resolution elastic-scattering measurements. Unique spin assignments for 15 and parity assignments for 11 resonance levels were obtained. The observed resonance strengths $\frac{(2J+1){\ensuremath{\Gamma}}_{\ensuremath{\gamma}}{\ensuremath{\Gamma}}_{p}}{\ensuremath{\Gamma}}$ vary between 0.077 and 14 eV. Several unusually broad odd-parity resonances were observed which have large reduced widths for $p$-wave and $f$-wave capture. The strong contribution of $1{f}_{\frac{7}{2}}$, $2{p}_{\frac{3}{2}}$, and $2{p}_{\frac{1}{2}}$ orbitals to the configuration of states near ${E}_{x}=7$ MeV in ${\mathrm{P}}^{30}$ is revealed. The influence of isobaric spin on the level structure and $\ensuremath{\gamma}$-ray decay properties is apparent. The ${2}^{\ensuremath{-}}$ resonances at ${E}_{p}=1470 \mathrm{and} 1686$ keV and the ${4}^{\ensuremath{-}}$ doublet at 1505 keV are identified as $T$-admixed pairs. Significant revisions of the decay schemes of the 1.45-, 2.94-, 4.14-, 4.50-, and 4.92-MeV levels have resulted from the 40-cc Ge(Li) spectra. The "4.92-MeV level" is shown to be a doublet with components at 4.921\ifmmode\pm\else\textpm\fi{}0.002 and 4.945\ifmmode\pm\else\textpm\fi{}0.005 MeV. By combining results of the angular-correlation, linear-polarization, and lifetime measurements, the following ${J}^{\ensuremath{\pi}}$ assignments are derived for bound levels: 0.71(${1}^{+}$), 1.45(${2}^{+}$), 1.97(${3}^{+}$), 2.54(${3}^{+}$), 2.72(${2}^{+}$), 2.84(${3}^{+}$), 2.94(${2}^{+}$), 3.02(${1}^{+}$), 4.14(${2}^{\ensuremath{-}}$), 4.18(${2}^{+}$), 4.23(${4}^{\ensuremath{-}}$), 4.43(${2}^{+}$), 4.47(${0}^{+}$), 4.50(${1}^{+}$), 4.62(${3}^{\ensuremath{-}}$), 4.92(${5}^{\ensuremath{-}}$ or ${3}^{\ensuremath{-}}$), and 4.94(1). Previous $T=1$ assignments for the bound levels at ${E}_{x}=0.68, 2.94, 4.18, 4.47, \mathrm{and} 4.50$ MeV are strongly supported by the data. Prominent "analog-to-antianalog" $M1$ transitions similar to those in other $s\ensuremath{-}d$ shell nuclei are observed. An average isospin impurity of 7% for levels below 7 MeV in ${\mathrm{P}}^{30}$ is derived from the set of $E1$ transition rates. On the average, the $E2$ transition rates have strengths slightly less than one Weisskopf unit. However, strong $E2$ enhancement is observed for the 2.94\ensuremath{\rightarrow}0.68, 2.54\ensuremath{\rightarrow}0, and 2.72\ensuremath{\rightarrow}0 transitions which have strengths of 21, 15, and 9 Weisskopf units, respectively. Several of the observed odd-parity resonance and bound levels appear to correspond to $T=1$ and $T=0$ members of a two-nucleon spectrum with major components (${s}_{\frac{1}{2}}{f}_{\frac{7}{2}}$), (${d}_{\frac{3}{2}}{f}_{\frac{7}{2}}$), and (${s}_{\frac{1}{2}}{p}_{\frac{3}{2}}$).

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