  All-electron variational and diffusion quantum Monte Carlo calculations of
the ground state energies of the first row atoms (Li to Ne) are reported. We
use trial wavefunctions of four types: single determinant Slater-Jastrow
wavefunctions; multi-determinant Slater-Jastrow wavefunctions; single
determinant Slater-Jastrow wavefunctions with backflow transformations;
multi-determinant Slater-Jastrow wavefunctions with backflow transformations.
At the diffusion quantum Monte Carlo level and using our best trial
wavefunctions we recover 99% or more of the correlation energy for Li, Be, B,
C, N, and Ne, 97% for O, and 98% for F.
