In the present work, we focus on reactions around ${}^{85}\mathrm{Rb}$, relevant to the astrophysical $\gamma$ process, where reaction flow is defined by the competition between two channels, the $(\gamma ,n)$ and the $(\gamma ,p)$. The $(\gamma ,p)$ channel was constrained in a previous measurement of the ${}^{84}\mathrm{Kr}(p,\gamma ){}^{85}\mathrm{Rb}$ reaction at Michigan State University using the Summing NaI(Tl)(SuN) detector. Here we present a reanalysis of the same data in which we provide new values for the reaction cross section, and in addition, we use the $\gamma$-ray spectra to constrain the statistical properties of ${}^{85}\mathrm{Rb}$, namely the nuclear level density (NLD) and the $\gamma$-ray strength function ($\gamma \mathrm{SF}$). Using these experimental inputs, we were able to provide a more stringent constraint on the ${}^{85}\mathrm{Rb}(\gamma ,n){}^{84}\mathrm{Rb}$ reaction channel. In addition, the proton optical model potential (pOMP) parameters were modified to obtain a better fit on the experimental data of $(p,\gamma ), (p,n)$, and $(p,2n)$ reaction channels. The constrained NLD and $\gamma \mathrm{SF}$, as well as the modified pOMP, were used to calculate the astrophysical reaction rates for the ${}^{85}\mathrm{Rb}(\gamma ,p){}^{84}\mathrm{Kr}$ and ${}^{85}\mathrm{Rb}(\gamma ,n){}^{84}\mathrm{Rb}$ channels. Based on our results, we conclude that the $(\gamma ,n)$ channel dominates at temperatures relevant for the production of the light $p$ nuclei.

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• Gamma-ray strength functions
• Level densities
• Nuclear astrophysics
• Nuclear physics of explosive environments
• Nucleosynthesis in explosive environments
• 59 ≤ A ≤ 89