  We study the effect of virtual Coulomb break-up, commonly known as the dipole
polarizability, of the deuteron projectile on the astrophysical fusion reaction
3He(d,p)4He. We use the adiabatic approximation to estimate the potential shift
due to the E1 transition to the continuum states in the deuteron, and compute
the barrier penetrability in the WKB approximation. We find that the
enhancement of the penetrability due to the deuteron break-up is too small to
resolve the longstanding puzzle observed in laboratory measurements that the
electron screening effect is surprisingly larger than theoretical prediction
based on an atomic physics model. The effect of the 3He break-up in the
3He(d,p)4He reaction, as well as the 7Li break-up in the 7Li(p,alpha)4He
reaction is also discussed.
