The ($p, d$) reaction has been performed at 25 MeV incident energy, on a rare ${}_{}{}^{190}{}_{}{}^{}\mathrm{Pt}$ target (35%) and on targets of ${}_{}{}^{192}{}_{}{}^{}\mathrm{Pt}$ (57%) and natural Pt. In ${}_{}{}^{189}{}_{}{}^{}\mathrm{Pt}$, eleven levels are observed up to 600 keV. In ${}_{}{}^{191}{}_{}{}^{}\mathrm{Pt}$, 18 levels are observed, four for the first time, up to 925 keV. Mass excesses are deduced for ${}_{}{}^{191}{}_{}{}^{}\mathrm{Pt}$, ${}_{}{}^{190}{}_{}{}^{}\mathrm{Pt}$, ${}_{}{}^{189}{}_{}{}^{}\mathrm{Pt}$, and ${}_{}{}^{188}{}_{}{}^{}\mathrm{Pt}$. Comparison of the experimental angular distributions with distorted-wave Born approximation calculations allows the determination of parity and spin limits for most of the final levels. Spectroscopic factors are deduced. Comparison with preceding experiments on heavier isotopes shows a smooth variation for the observed strengths between $A=197\mathrm{}$ and $A=189\mathrm{}$, with a minimum fragmentation of the $l=1\mathrm{}$ strength in ${}_{}{}^{193}{}_{}{}^{}\mathrm{Pt}$.

NUCLEAR REACTIONS ${}_{}{}^{192,190}{}_{}{}^{}\mathrm{Pt}(p, d)$, $E=25\mathrm{}$ MeV; ${}_{}{}^{191,190,189,188}{}_{}{}^{}\mathrm{Pt}$ deduced mass excesses; measured $\sigma \left(\theta \right)$; ${}_{}{}^{191,189}{}_{}{}^{}\mathrm{Pt}$ deduced levels, $E$, $J$, $\pi$, $S$.

• Received 8 May 1980

DOI:https://doi.org/10.1103/PhysRevC.22.997