The distribution of ${\mathrm{N}}^{13}$ particles from the neutron transfer reaction ${\mathrm{N}}^{14}$ (${\mathrm{N}}^{14}$, ${\mathrm{N}}^{13}$) ${\mathrm{N}}^{15}$ was investigated from 3.5-32° in the laboratory. Range curves for ${\mathrm{N}}^{13}$ particles were obtained from 16-32° (laboratory system). Transfers leaving both residual nuclei in their ground states were distinguished from those in which the products are left in excited states. It is found that (1) the ground-state transfer cross section decreases as the bombarding energy is lowered; (2) of the ${\mathrm{N}}^{15}$ excited states, only the first and/or second contribute significantly to the transfer cross section; (3) for a given bombarding energy the excited-state transfer distribution peaks at an angle larger than that at which the ground-state transfer distribution reaches its maximum; (4) from the ground-state transfer distribution an $r_0$ of 2.2 f can be determined, while the excited-state transfer distribution yields an $r_0$ of about 1.65 f; and (5) the excited-state distributions are more consistent with the tunneling mechanism of Breit and Ebel than are the ground-state distributions.

• Received 2 March 1961

DOI:https://doi.org/10.1103/PhysRev.123.582