Nuclear polarization in d and t atoms and in the dt molecule

Deuteron polarization in a d atom and triton polarization in a t atom were investigated on the basis of a three- (four-) body model of the d- (t-) system. Virtual excitation of the deuteron and triton is treated within the second-order perturbation theory. The nuclear polarization energy is obtained as -9.9 meV for the d atom and -1.1 meV for the t atom. We examined the validity of the adiabatic approximation and the dipole approximation which were employed in the literature calculation of the deuteron polarization; the approximations were found to be rather poor. Deuteron and triton polarization potentials were derived and were found to deviate much, in the internal region, from the r-4-type potential, which is given by the adiabatic and dipole approximations. With the use of these potentials, correction to 11 due to the nuclear polarization in the dt molecule at the J=v=1 state was calculated to be -1.7 meV, which should significantly affect the resonant formation of the state, a key to the muon catalyzed d-t fusion.