The quantum effect on the critical point of permanent gas is explained with J. de Boer's corresponding principle by means of simple lattice gas theory. We suppose the entropy difference, between the states when all nearest neighbour lattice points are occupied by other atoms and are vacant entirely, is proportional to quantum effect parameter Δ*=h/√m∈·σ. Under this supposition, the result is agree with experimental value except nitrogen.
The deviation of critical point of nitrogen is due to unspherical form of molecule, and we discuss the relation between the lattice gas theory and our result.
