AbstractFor monosubstituted benzenes (Ph‐Z), Linderberg et al. demonstrated the validity of the equation ΔCEBE ≈ κσ, where ΔCEBE is the difference between the core‐electron binding energies (CEBE) of a specific carbon in monosubstituted benzene derivatives (Ph‐Z) and that of unsubstituted benzene (Ph‐H), κ is related to the reaction constant and σ is the experimental Hammett sigma constant. CEBEs of carbon atoms for a series of Ph‐Z were calculated using density functional theory (DFT) with the scheme ΔEKS(PW86‐PW91)/TZP+Crel//HF/6‐31G*. An average absolute deviation of 0.15 eV was obtained with respect to observed values. A linear regression analysis of the form Y = A+BX of a plot of, for instance, Hammett σp‐constants against calculated ΔCEBEs (in eV) at para‐carbon for n = 11 produced a value of A = −0.1310 and B = 1.056 with a correlation coefficient R = 0.983, a standard deviation of 0.099 and a p‐value < 0.0001. Copyright © 2004 John Wiley & Sons, Ltd.