  Neutrino emissions from electron/positron capture on the deuteron and the
nucleon-nucleon fusion processes in the surface region of a supernova core are
studied. These weak processes are evaluated in the standard nuclear physics
approach, which consists of one-nucleon and two-nucleon-exchange currents and
nuclear wave functions generated by a high precision nucleon-nucleon potential.
In addition to the cross sections for these processes involving the deuteron,
we present neutrino emissivities due to these processes calculated for typical
profiles of core-collapsed supernovae. These novel neutrino emissivities are
compared with the standard neutrino emission mechanisms. We find that the
neutrino emissivity due to the electron capture on the deuteron is comparable
to that on the proton in the deuteron abundant region. The implications of the
new channels involving deuterons for the supernova mechanism are discussed.
