Gamma-Ray Transitions inA=35Nuclei

The mean lifetime of the 1.99-MeV ${\frac{7}{2}}^{-}$ level of ${\mathrm{S}}^{35}$ was determined by a measurement of the delayed coincidence between protons and $\gamma$ rays in the reaction ${\mathrm{S}}^{34}(d,p\gamma ){\mathrm{S}}^{35}$ at $E_d=4.48\mathrm{}$ MeV, with the result ${\tau }_m=1.47\mathrm{}\pm 0.07$ nsec. The $\gamma$ decay of the ${\frac{7}{2}}^{-}$, $T=\frac{3}{2}$ analog of this level at $E_x=7.55\mathrm{}$ MeV in ${\mathrm{Cl}}^{35}$ was examined in detail with large-volume Ge(Li) detectors and Ge(Li)-NaI(Tl) coincidence techniques. The $\gamma$-ray spectra obtained at the analog state, which appears as a well-known resonance at $E_p=1211\mathrm{}$ keV in the reaction ${\mathrm{S}}^{34}(p,\gamma ){\mathrm{Cl}}^{35}$, revealed the presence of several previously unknown transitions in addition to the known strong analog-to-antianalog $M1\mathrm{}$ transition to the ${\frac{7}{2}}^{-}$, $T=\frac{1}{2}$ level at 3.16 MeV. Examples are a crossover $M2\mathrm{}$ transition from the analog resonance to the ${\frac{3}{2}}^{+}$ ground state of ${\mathrm{Cl}}^{35}$ with a strength of 3.0 ± 0.8 Weisskopf units, a mixed $E1\mathrm{}-M2\mathrm{}$ transition ($\delta =0.44\mathrm{}\pm 0.12$) from the ${\frac{7}{2}}^{-}$ antianalog state to the ${\frac{5}{2}}^{+}$ level at 1.76 MeV, and a 160-keV transition between the antianalog state and the ${\frac{5}{2}}^{+}$ level at 3.00 MeV. Weak transitions which can be interpreted as members of cascades through levels in the region $E_x=4.3-5.7\mathrm{}$ MeV were also identified. It is shown that the $M1\mathrm{}$, $E2\mathrm{}$, $M2\mathrm{}$, and $E3\mathrm{}$ strengths of transitions connecting members of the system of parent, analog, antianalog, and ground states can be accurately reproduced by a simple model based upon an inert ${\mathrm{S}}^{32}$ core with active nucleons in the $d_{\frac{3}{2}}$ and $f_{\frac{7}{2}}$ orbits, with bare-nucleon $g$ factors for the magnetic transitions, and with reasonable effective charges for the electric transitions. The wave functions for the ${\frac{7}{2}}^{-}$ levels derived from this model are used to predict strengths of mirror transitions in ${\mathrm{Ar}}^{35}$ and ${\mathrm{K}}^{35}$.