To compare with the wealth of new data on alpha-accompanied fission of ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}$* we have made new trajectory calculations. Initial conditions for several parameters were selected from Gaussian distributions by the Monte Carlo method and about 15 000 trajectories were run for an alpha source at the electrostatic saddle point. Momentum and energy are fully conserved in the three-body problem, though the usual point charge approximation without nuclear forces was used. The main calculations center the alpha source at the electrostatic saddle. General agreement with experiment is remarkable including even the appearance of low-energy secondary peaks at large angles. Effects of shifting the source from the saddle point toward either fragment are studied, running an additional 15 000 trajectories for each of two shifts. Both the satellite peak phenomena and the angular distribution indicate the need for a small shift of source toward the light fragment.

NUCLEAR REACTIONS Alpha accompanied thermal neutron ternary fission ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}(n, f)$. Monte Carlo theory; trajectory calculations; $\alpha$-particle angular and energy distributions.

• Received 29 March 1982

DOI:https://doi.org/10.1103/PhysRevC.26.2049