The substituent effect in substituted n-decanes (1-X-decan), chain sigma-systems of saturated hydrocarbon, and C-3 substituted gonanes (3-X-gonane), fused ring sigma-systems, where X = H, NO2, CHO, F, CH3, Bu-t (tertiary butyl), was investigated using calculated core electron binding energies. The energies were calculated using the density-functional theory (DFT) with the Perdew-Wang 1986 exchange and the Perdew-Wang 1991 correlation functionals. A triple-zeta polarized Slater type basis set was employed. The effect of the electron withdrawing substituents, NO2, F, and CHO, is felt all the way to the end of the 10-carbon chain in 1-X-decane. Similarly, the effect of the electron withdrawing substituents is felt to the D ring carbons in 3-X-gonane. A possible explanation of the long-range effect is given. It was shown that the substituent effect was very similar, but not identical, in 1-X-decane and 3-X-gonane in quality and quantity. (C) 2013 Elsevier B.V. All rights reserved.1024914Fundacao de Amparo a Pesquisa do Estado de Amazonas (FAPEAM)