  The possibility of significant systematic errors due to the use of 1D
homogeneous atmospheres in lithium-abundance determinations of cool stars
motivates a study of non-local-thermodynamic-equilibrium (NLTE) effects on Li I
line formation in a 3D solar-granulation simulation snapshot. The NLTE effect
on the equivalent width of the 671 nm resonance line is small in 1D models or
in integrated light from the granulation model. The line-strength variations
over the granulation pattern are however markedly different in NLTE compared to
LTE -- observations of this may provide diagnostics to NLTE effects. The
effects of horizontal photon exchange found in the granulation model are
moderate and due entirely to bound-bound processes, ultraviolet overionization
is unimportant.
