Internal Conversion, Multipole Mixing, and Auger Spectrum in Zn 67 from Ga 67 </mml:msup…
1966; American Institute of Physics; Volume: 151; Issue: 3 Linguagem: Inglês
10.1103/physrev.151.886
ISSN1536-6065
AutoresM. S. Freedman, F. T. Porter, Frank Wagner,
Tópico(s)Advanced Chemical Physics Studies
ResumoAbsolute internal-conversion coefficients measured with high electron resolution and with a Ge(Li) spectrometer have been studied in seven transitions in ${\mathrm{Zn}}^{67}$ from 78-h ${\mathrm{Ga}}^{67}$ decay. From these and from $L$ subshell ratios for the three lowest energy transitions, we deduce the following multipolarities: 93 keV, pure $E2;184 \mathrm{keV},M1+(8\ensuremath{-}12% E2)$; all others predominantly $M1$, with $E2$ required in the 91- and 494-keV transitions. The retardation factor of the $l$-allowed 91-keV transition is 500, which is larger than that (340) for the $l$-forbidden 184-keV transition ($E2$-component enhancement of 17) originating at the same level. Conversion data, together with a reanalysis of $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ angular-correlation measurements of Rietjens and Van den Bold, lead unambiguously to the following level spin assignments, in agreement with those from ($d,p$) stripping and Coulomb excitation: ($\mathrm{keV},J\ensuremath{\pi}$); ground state $\frac{5}{2}\ensuremath{-}$; 93.317\ifmmode\pm\else\textpm\fi{}0.02, \textonehalf{}---; $184.595\ifmmode\pm\else\textpm\fi{}0.04,\frac{3}{2}\ensuremath{-};393.59\ifmmode\pm\else\textpm\fi{}0.04,\frac{3}{2}\ensuremath{-};887.87\ifmmode\pm\else\textpm\fi{}0.1,\frac{3}{2}\ensuremath{-}$. Conversion coefficients show somewhat better agreement with those calculated by Sliv and Band (extrapolated from $Z=33$) than with those of Rose for the $L$ shell, but indicate that both computations give $L$-shell coefficients too small (\ensuremath{\sim}10% for Sliv and Band, \ensuremath{\sim}20% for Rose) for this $Z$ range. The empirical $Z$ displacement rule for ${M}_{I}$ conversion due to Chu and Perlman ($\ensuremath{\Delta}Z=\ensuremath{-}7.0$), which, applied to the unscreened, point-nucleus $M$ conversion values of Rose gives agreement for all energies and multipolarities above $Z=50$, is found to require $\ensuremath{\Delta}Z=\ensuremath{-}9.5$ for agreement at $Z=30$. Six of nine predicted lines in the KLL Auger spectrum of Zn are resolved; energies determined are 7-13 eV above those calculated by H\"ornfeldt, and intensities agree with recent experimental results at $Z=32$ except for the $K\ensuremath{-}{L}_{1}{L}_{3}(^{3}P_{1})$ line, where our intensity is lower by a factor of 2.
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