  We present Quantum Monte Carlo calculations of the properties of a
two--component mass imbalanced Fermi gas, corresponding to the $^6$Li--$^{40}$K
mixture. We compute the equation of state of the unpolarized system as a
function of the scattering length with particular attention paid to the unitary
limit, where the effect of the effective range of the interaction is explored.
We have also computed the pair distribution function and the momentum
distribution over a range of interaction strengths to provide information about
the structure of the system. Finally, we have computed the heavy/light
quasiparticle spectrum. Our theoretical predictions, based on Quantum Monte
Carlo calculations, can be tested by future experiments with ultracold
fermionic gases.
