  A new acceleration algorithm to address the problem of multiple time scales
in variational Monte Carlo simulations is presented. After a first attempted
move has been rejected, the delayed rejection algorithm attempts a second move
with a smaller time step, so that even moves of the core electrons can be
accepted. Results on Be and Ne atoms as test cases are presented. Correlation
time and both average accepted displacement and acceptance ratio as a function
of the distance from the nucleus evidence the efficiency of the proposed
algorithm in dealing with the multiple time scales problem.
