Applicability of resonant two-photon ionization in supersonic beam mass spectrometry to halogenated aromatic hydrocarbons

摘要: In this work, problems are studied that may arise in the use of resonant two-photon ionization as an source supersonic beam mass spectrometry. The particular classes molecules herein include mono- and disubstituted halogenated benzenes toluene, pheno, aniline derivatives. a simple one-color R2PI scheme many ortho-substituted compounds found not to ionize efficiently. This appears be due combination steric coulombic interactions between adjacent substituent groups raise potential molecule relative unsubstituted case also decrease Franck-Condon transition probability for absorption thus making difficult. These effects have been qualitatively related overall electron releasing withdrawing properties so reasonable predictions can made regarding which substituted will amenable technique. para-substituted there is little interaction groups, generally occur However, cases such iodo-substituted where does apparently ultrafast radiationless processes. 57 references, 5 figures, tables.