Isomeric ratios of the yields of the reactions /sup 197/Au(. gamma. ,n)/sup 196m/,gAu and /sup 197/Au(e,e'n)/sup 196m/,gAu at energies10--90 MeV

Isomeric ratios of the yields of the (..gamma..,n) and (e,e'n) reactions have been measured by an activation method in the nuclei /sup 197/Au with formation of high-spin states (J/sup ..pi../ = 12/sup -/) of /sup 196/Au. The dependence obtained for the isomeric ratio for (..gamma..,n) reactions kappa-cur-bar/sub ..gamma../ on E/sub gammamax/ has the form of a saturation curve. In the saturation region the value is kappa-cur-bar/sub ..gamma../ = (6.1 +- 0.4) x 10/sup -4/. Analysis of the dependence kappa-cur-bar/sub ..gamma../(E/sub gammamax/) permits the hypothesis that for the (..gamma..,n) reaction the formation of this state has a threshold approx.12 MeV. The isomeric ratios kappa-cur-bar/sub e/ for the (e,e'n) reaction exceed the values of kappa-cur-bar/sub ..gamma../. This fact enabled us to conclude that there is an appreciable contribution to excitation of the high-spin state from the isovector quadrupole E2 resonance, which is in good agreement with estimates based on a simple model. However, the principal role in population of the isomeric state apparently belongs to cascade ..gamma.. transitions.