  Radiation feedback from young star clusters embedded in giant molecular
clouds (GMCs) is believed to be important to the control of star formation. For
the most massive and dense clouds, including those in which super star clusters
(SSCs) are born, pressure from reprocessed radiation exerted on dust grains may
disperse a significant portion of the cloud mass back into the interstellar
medium (ISM). Using our radiaton hydrodynamics (RHD) code, Hyperion, we conduct
a series of numerical simulations to test this idea. Our models follow the
evolution of self-gravitating, strongly turbulent clouds in which collapsing
regions are replaced by radiating sink particles representing stellar clusters.
We evaluate the dependence of the star formation efficiency (SFE) on the size
and mass of the cloud and $\kappa$, the opacity of the gas to infrared (IR)
radiation. We find that the single most important parameter determining the
evolutionary outcome is $\kappa$, with $\kappa \gtrsim 15 \text{ cm}^2 \text{
g}^{-1}$ needed to disrupt clouds. For $\kappa = 20-40 \text{ cm}^2 \text{
g}^{-1}$, the resulting SFE=50-70% is similar to empirical estimates for some
SSC-forming clouds. The opacities required for GMC disruption likely apply only
in dust-enriched environments. We find that the subgrid model approach of
boosting the direct radiation force $L/c$ by a "trapping factor" equal to a
cloud's mean IR optical depth can overestimate the true radiation force by
factors of $\sim 4-5$. We conclude that feedback from reprocessed IR radiation
alone is unlikely to significantly reduce star formation within GMCs unless
their dust abundances or cluster light-to-mass ratios are enhanced.
