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Mass spectrum and heat of formation of isocyanic acid. Production of [hco] + from discrete electronic state of molecular ion
Author(s) -
Compernolle F.
Publication year - 1975
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.1210100407
Subject(s) - isocyanic acid , ion , chemistry , metastability , atomic physics , molecule , adiabatic process , polyatomic ion , ground state , analytical chemistry (journal) , physics , organic chemistry , thermodynamics , chromatography
The appearance potentials for the transition ([HNCO] +· → [HCO] + + N), determined for the reaction in the ion source and in the first field free region (15·84 and 15·52 eV) correspond, respectively, to the vertical and adiabatic third ionisation potential of HNCO, as determined by photoelectron spectroscopy. The formyl ion and nitrogen radical are formed in the ground state, which requires predissociation of a quartet molecular ion of HNCO. A heat of formation δ H f(HNCO)g = −25 ± 3 kcal mol ·1 was determined from the appearance potential and kinetic energy release for the metastable ion [HCO] + , and from the difference in appearance potentials for the ion [NH] + · produced from the isoelectronic molecules HNCO and HN 3 .