ISSN:
0030-493X
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Doubly charged ion mass spectra of alkyl-substituted furans and pyrroles were obtained using a double-focusing magnetic mass spectrometer operated at 3.2 kV accelerating voltage. Molecular ions were the dominant species found in doubly charged spectra of lower molecular weight heterocydic compounds, whereas the spectra of the higher weight homologues were typified by abundant fragment ions from extensive decomposition. Measured doubly charged ionization and appearance energies ranged from 22.8 to 47.9 eV. Ionization energies were correlated with values calculated using self-consistent field-molecular orbital techniques. A multichannel diabatic curve-crossing model was developed to investigate the fundamental organic ion reactions responsible for development of doubly charged ion mass spectra. Probabilities for Landau-Zener type transitions between reactant and product curves were determined and used in the collision model to predict charge-transfer cross-sections, which compared favorably with experimental cross-sections obtained using time-of-flight techniques.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/oms.1210220703
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