Electron–Positron Pair Creation in Asymmetric Collisions of Heavy Nuclei

Previously developed two-center approach for calculations of electron–positron pair creation in collisions of two identical heavy nuclei is extended to nonsymmetric collisions where the colliding nuclei differ from each other. The time-dependent Dirac equation for the positron wave function is solved numerically with the help of the generalized pseudospectral method in modified prolate spheroidal coordinates and Crank–Nicolson algorithm for time propagation. For the case of the asymmetric U^92 + - Cm^96 + collisions, we calculate total probabilities of electron–positron pair creation, as well as angle-integrated and angle-resolved energy distributions of the emitted positrons. Characteristic signatures of the supercritical regime are found in total probabilities and energy distributions. The angular distributions show high degree of isotropy.