A premixed laminar n-heptane/air flame (1 atm and phi = 1.0 +/-0.05) was investigated experimentally (using on-line GC/MS) and computationally. Ethene, propene, 1-butene, 1-pentene, 1-hexene, and 1-heptene showed broad peaks with maxima at a distance around 1000 mu m from the burner. Methane, ethane, and propane showed more narrow peaks and; maxima around 1075 mu m. The following compounds with their maxima were found (mol %): ethene (0.99), methane (0.069), propene (0.127), ethyne (0.103), ethane (0.080), 1-butene (0.040), 1-pentene (0.021), and 1,3-butadiene (0.014). Concentrations of less than 0.01 mol % were detected for the components 1-heptene, propyne, propadiene, methanol, and acetaldehyde. The flame was modeled using the semiempirical mechanism by Held et al.(1) The model produced peaks of the organic intermediates at about 400-500 mu m. Important measured species not present in the mechanism were propane, propyne, methanol, isobutene, 2-butene, and 1-heptene. The computed maxima of 1-but ene, 1,3-butadiene, and 1-pentene were higher than the experimental maxima by a factor of about 2, 2, and 3, respectively. The model gives very similar results for two different pressures, 1 and 0.06 atm, except: for a common scaling factor.