Photoelectron Spectra of Molecules. I. Ionization Potentials of Some Organic Molecules and Their Interpretation

Abstract

The photoelectron spectra of 67 organic compounds, including paraffins, cycloparaffins, olefines, dienes, aromatic hydrocarbons, alcohols, ethers, aldehydes, ketones, and diene iron tricarbonyl complexes, have been measured, using a simple retarding‐potential grid‐type spectrometer, and the results interpreted in terms of a recently developed semiempirical SCF MO treatment (MINDO approximation). The observed ionization potentials show a remarkably close relationship to the calculated Hartree–Fock MO energies over the whole range of ionization potentials (<20 eV) studied. An estimate is given for the first ionization potential of cyclobutadiene.