4He D-state effects in the 2H(d, gamma )4He reaction at low energies.

The /sup 2/H(d, ..gamma..)/sup 4/He cross section was measured for deuteron laboratory energies between 0.7 and 4.5 MeV. Angular distributions were obtained at laboratory energies of E-italic/sub d/ = 1.38, 2.05, 9.6, and 15.0 MeV. These data indicate that the D-italic state of /sup 4/He, which can be populated via S-italic-wave capture in this reaction, has a large effect on the energy and angle dependence of this low energy capture cross section. The data are shown to imply an asymptotic D-italic-to-S-italic state ratio rho = -0.2 +- 0.05. The implication of this observation for the absolute cross section below 1.0 MeV is discussed.