  Bubble chambers are promising technologies for detecting low-energy nuclear
recoils from the elastic scattering of dark matter particle candidates. Bubble
nucleation occurs when the energy deposition exceeds a specific threshold
defined traditionally by the "heat-spike" Seitz threshold. In this paper, we
report on a physical model that can account for observed discrepancies between
the current Seitz model and the measured nucleation efficiency of low-energy
nuclear recoils, which is necessary for interpreting dark matter signals. In
our work, we combine molecular dynamics and Monte Carlo simulations together
with the Lindhard model to predict bubble nucleation efficiency and energy
thresholds for C$_3$F$_8$, CF$_3$I, and xenon with enhanced accuracy over the
Seitz model when compared to existing experimental data. We use our model to
determine the effect on cross-section limits for spin-dependent and
spin-independent interactions and compare it to the current PICO dark matter
experiment. Our technique can also be applied to estimate the efficiency of
future target fluids where no experimental data are available. As an example,
we predict the nucleation efficiency, the energy threshold and the
cross-section limits in the spin-independent channel for the Scintillating
Bubble Chamber experiment filled with superheated liquid argon.
