Derivation of P E Functions

Figuro 7.4. Photoelectron spectrum of Nj (left, vertical energy scale), corresponding electronic/vibrational energy levels of N2 and 2 molecular orbitals of N2 (Bahr 1973, with permission). 

For such larger molecules, their initial internal energy must be added to that resulting from ionization (hot bands of lower IE result only from vibrational excitation in the electronic state from which ionization occurs). Lowering the sample temperature before ionization can thus increase [M ] and affect product abundances (Maccoll 1986 Bowen and MaccoU 1989 Brauers and von Bunau 1990). The most dramatic effects have been achieved with supersonic expansion of the sample beam (Amirav 1991), finding peaks with El from a large proportion of molecules that do not show these in their normal mass spectra. 

More precise methods are available to study the dissociation of ions formed with specific amounts of internal energy. Charge exchange can be specific, e.g., lE(Ar) = 15.75973 + 0.00001 if 1E(M) = 10.0 eV, neutralization of Ar (ground 

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