In this paper, calculation of nine first-row diatomic dissociation energies (D-e) and six first-row heterodiatomic equilibrium dipole moments (mu(e)) highlights the strength of Ornstein-Uhlenbeck diffusion quantum Monte Carlo with the fixed-node approximation. By combining explicitly correlated wave functions based on spherical Gaussian-type orbitals and geminals obtained by an optimization of energy functional, it was possible to achieve satisfied agreement with experiment in most cases. Calculations on the molecules LiH, Li-2, BH, BF, HF, LiF, CO, N-2, and F-2 are presented. This work gives an accuracy that is comparable to or better than previous theoretical estimates. We also compare the performance of three different approximations in estimating dipole moments of molecules. (C) 2003 American Institute of Physics.