| Abstract: | Wavelength-dependent effects in the resonance-enhanced multiphoton ionization/fragmentation mass spectra of p-chloroaniline and diphenyl ether are presented. For both molecules, the formation of low-energy fragments can be discriminated against in favor of higher-energy fragments by using ‘low’-energy radiation (290 nm region) for ionization/fragmentation. The same low-energy fragments become dominant when higher-energy radiation (266 nm) is used. This unique behavior is explained in terms of the narrow distribution of parent ion internal energies created through resonance-enhanced multiphoton ionization/fragmentation and the competing kinetic processes accessed by the parent ion as it absorbs each successive photon. |
