<p>The energetics of interactions between gaseous atoms and pyorolytic graphite (PG) were investigated by the Gibbs free energy change (<i>ΔG</i>) determined from the back edge of atomic absorption (AA) signa. The Gibbs free energy was estimated by assuming an equilibrium state among the interactions between an analyte atom (M) and a PG surface. Because of its poor reactivity, lead was used as a standard to define a <i>ΔG</i> value of Zero to calculate the loss rate of a hypothetical M_(g) without interactions. The kinetic parameters for M were calculated using a diffusion loss model. The ratio of the experimental loss rate to the hypothetical loss rate was used to determine the equilibrium constant (<i>K</i>) for the interaction between M and the PG surface, from which <i>ΔG</i> was calculated. The slope of a linear relationship of <i>ΔG</i> vs. the activation energy (<i>E</i>_a) of atomization for individual atoms on the PG surface was consistent with that of <i>ΔG</i> vs. the binding energy of adatoms with graphene. It was proposed that the interaction between M_(g) and the PG surface was caused by the binding to sites of top-C for Au, C–C bridge for Ag and Pb, a hexagonal hole of sixfold sites within C-ring for Co, Fe and Ni, a pair of terminal-C on zigzag edge for Cr, top-subedge for Mn, and active sites in adjacent graphite layers controlling intercalation for Cu.</p> Graphical abstract <p></p>