Emission-angle dependence of fission fragment spin

The average spin of fission fragment at specific mass asymmetry has been obtained as a function of emission angles in the ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ (${\mathrm{\alpha }}_{39.1\mathrm{M}\mathrm{e}\mathrm{V}}$,f) system from radiochemically determined independent isomeric yield ratios of ${}_{}{}^{132}{}_{}{}^{}\mathrm{I}$. The fragment average spin is seen to decrease from 11.2ħ to 6.5ħ with change in emission angle from 90° to 20°, due to the angle-dependent tilting component over and above the statistical wriggling, bending, and twisting components as per the collective mode model. Effects of entrance channel parameters and multichance fission are also discussed.