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MNDO study of fragmentations in mass spectrometry. Part I. The geometry and electron structure of [C 3 H 6 O] + ˙ systems and [C 2 H 3 O] + ions
Author(s) -
Hrušák Jan,
Tkaczyk Martin
Publication year - 1989
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210241104
Subject(s) - mndo , chemistry , ab initio , ionization , electron ionization , standard enthalpy of formation , mass spectrometry , ionization energy , ab initio quantum chemistry methods , electron , atomic physics , crystallography , computational chemistry , physics , molecule , ion , nuclear physics , organic chemistry , chromatography
MNDO calculations of [C 3 H 6 O] + ˙ predict the parallel existence of both structures of radical cations of acetone (1) and propen‐2‐ol (2) in electron ionization spectra. The calculated heats of formation of 1 + ˙ (Δ H f MNDO = 783.2 kj mol −1 ) and of 2 + ˙ (Δ H f MNDO = 649.8 kJ mol −1 ) are in very good agreement with the experimental results. A comparison with the results of ab initio calculations (3–21 G and 6–31 G) and experimental data for the individual structures of the main fragment [C 2 H 3 O] + demonstrates a sufficient accuracy of MNDO results, suggesting the possibility of applying the method also in other cationic systems, especially in larger ones.