  A compact yet accurate approach for representing the wave functions of
members of the He and Li isoelectronic series is using explicitly correlated
wave functions. These wave functions, however, often have nonlinear forms,
which make them challenging to optimize. In this work, we show how Variational
Monte Carlo (VMC) can efficiently optimize explicitly correlated wave functions
that accurately describe the quartet 1s2s2p state of the Li isoelectronic
sequence with ten or fewer parameters. We find that our compact wave functions
correctly describe cusp conditions and reproduce at least 99.9% percent of the
exact energy.
