  We introduce a basis set consisting of three-dimensional Deslauriers--Dubuc
wavelets and solve numerically the Schr\"odinger equations of H and He atoms
and molecules $\mathrm{H}_2$, $\mathrm{H}_2^+$, and $\mathrm{LiH}$ with HF and
DFT methods. We also compute the 2s and 2p excited states of hydrogen. The
Coulomb singularity at the nucleus is handled by using a pseudopotential. The
eigenvalue problem is solved with Arnoldi and Lanczos methods, Poisson equation
with GMRES and CGNR methods, and matrix elements are computed using the
biorthogonality relations of the interpolating wavelets. Performance is
compared with those of CCCBDB and BigDFT.
