Convergence features in the pseudostate theory of the d+α system

Convergence properties of the pseudostate method in the d+α system are investigated with respect to the number of deuteron Gaussian basis functions and the number of pseudo-inelastic configurations. Results indicate that the deuteron specific distortion effect can be well described by using about 10 to 15 Gaussian basis functions to generate deuteron wave functions in the ground and pseudo-excited states. Also, it is found that, for the ground-state energy of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ and for d+α scattering in the very low energy region, only deuteron pseudo-excited states with excitation energies less than about 60 MeV need to be included. In addition, the investigation shows that the calculated total reaction cross sections are rather severely underestimated, indicating that even more cluster configurations must be introduced into the resonating-group formulation in order to obtain a satisfactory explanation of all the important features of the six-nucleon system.