Valencehyphen;Shell Ionization Potentials of Halomethanes by Photoelectron Spectroscopy. I CH3Cl, CH3Br, CH3I. Vibrational Frequencies and Vibronic Interaction in CH3Brplus;and CH3Clplus;

摘要

Photoelectron spectra of methyl chloride, methyl bromide, and methyl iodide obtained with 584hyphen;Aring; radiation yield in each case four of the five valencehyphen;shell ionization potentials. Values of 11.29, 10.53, and 9.50 eV are obtained for the first ionization potentials, respectively, corresponding to ionization from halogen ldquo;lonehyphen;pairrdquo; orbitals. Resolved vibrational structure allows determination of frequencies of the corresponding normal vibrations of the positive ions in several cases. Relative intensities of vibrational components in the first ionization potential are dictated by vibronic interaction. Approximate values of the Jahnndash;Teller parametersDforngr;4, ngr;5, ngr;6in CH3Brplus;may be obtained from these intensities. Small values ofD lpar;Dthinsp;le;thinsp;0.1rpar;suffice to produce sizeable modifications of intensity for the intermediate spinndash;orbit splittings observed in these ions.