Nuclear spectroscopy with lithium beams. I. High-spin states inFe55,Mn55, andCr53

The ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ bombardment of ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$ has been used in conjuction with recoil distance lifetime (RDM), $\gamma -\gamma$ coincidence, angular distribution, and Doppler shift attenuation lifetime (DSAM) measurements to gain information on the properties of high-spin states in the nuclei ${}_{}{}^{55}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}$, and ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$. Mean lifetimes ($\tau$) determined by RDM were as follows—in ${}_{}{}^{55}{}_{}{}^{}\mathrm{Fe}$: 1409-keV level ($\tau =57.8\mathrm{}\pm 3.5$ psec), 2813 (14.5±3.1 psec), 5099 (32.3±1.1 psec); in ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}$: 126-keV level ($\tau =382\mathrm{}\pm 16$ psec); in ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$: 2173-keV level ($\tau =47\mathrm{}\pm 15$ psec); 3084 ($\tau =43\mathrm{}\pm 15$ psec). Tentative spin assignments were made as follows—in ${}_{}{}^{55}{}_{}{}^{}\mathrm{Fe}$: 5099-keV level $J=\left(\frac{19}{2}\right)$, 6528, $J=\left(\frac{21}{2}\right)$, in ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}$: 3056-keV level $J=\left(\frac{15}{2}\right)$. Lifetimes (or limits) were also established from DSAM measurements for a number of other levels in the above nuclei. The results are compared to shell model calculations.