Calculation of Ionization Potentials and C−H Bond Dissociation Energies of Toluene Derivatives

1996 ◽  
Vol 100 (8) ◽  
pp. 2950-2956 ◽  
Author(s):  
Thomas Fox ◽  
Peter A. Kollman
Keyword(s):  
Ionization Potentials ◽  
Bond Dissociation Energies ◽  
Bond Dissociation ◽  
Dissociation Energies

scholarly journals Zur Photoionisation und Ionenfragmentation von SF4/Photoionization and Ion Fragmentation of SF4

1989 ◽  
Vol 44 (1) ◽  
pp. 13-16 ◽  
Author(s):  
H.-W. Jochims ◽  
E. Rühl ◽  
H. Baumgärtel
Keyword(s):  
Mass Spectrometry ◽  
Photoelectron Spectroscopy ◽  
Theoretical Calculations ◽  
Ionization Potentials ◽  
Bond Dissociation Energies ◽  
Bond Dissociation ◽  
Photoionization Mass Spectrometry ◽  
Ion Fragmentation ◽  
Dissociation Energies

Abstract The ionization potentials of sulfurtetrafluoride have been measured using threshold photoelectron spectroscopy and com pared with theoretical calculations. The decay of SF4+ has been studied by photoionization mass spectrometry and photoion-photoelectron coincidence. The break-down graphs reveal competing decay processes. Bond dissociation energies in SF4+ have been calculated.

scholarly journals Thermochemistry of icosahedral closo-dicarboranes: a composite ab initio quantum-chemical perspective

2016 ◽  
Vol 94 (12) ◽  
pp. 1082-1089 ◽  
Author(s):  
Farzaneh Sarrami ◽  
Li-Juan Yu ◽  
Amir Karton
Keyword(s):  
Ab Initio ◽  
Poor Performance ◽  
Ionization Potentials ◽  
Thermochemical Properties ◽  
Bond Dissociation Energies ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
Explicitly Correlated ◽  
Experimental Values ◽  
High Level

We obtained accurate thermochemical properties for the ortho-, meta-, and para-dicarborane isomers (C2B10H12) by means of explicitly correlated high-level thermochemical procedures. The thermochemical properties include heats of formation, isomerization energies, C–H and B–H bond dissociation energies (BDEs), and ionization potentials. Of these only the ionization potentials are known experimentally. Our best theoretical ionization potentials, obtained by means of the ab initio W1–F12 thermochemical protocol, was 241.50 kcal mol–1 (para-dicarborane), 238.45 kcal mol–1 (meta-dicarborane), and 236.54 kcal mol–1 (ortho-dicarborane). These values agree with the experimental values adopted by the National Institute of Standards and Technology (NIST) thermochemical tables to within overlapping uncertainties. However, they suggest that the experimental values may represent significant underestimations. For all isomers, the C–H BDEs are systematically higher than the B–H BDEs because of the relative stability of the boron-centred radicals. The C–H BDEs for the three isomers cluster within a narrow energetic interval, namely between 110.8 kcal mol–1 (para-dicarborane) and 111.7 kcal mol–1 (meta-dicarborane). The B–H BDEs cluster within a larger interval ranging between 105.8 and 108.1 kcal mol–1 (both obtained for ortho-dicarborane). We used our benchmark W1–F12 data to assess the performance of a number of lower cost composite ab initio methods. We found that the Gaussian-3 procedures (G3(MP2)B3 and G3B3) result in excellent performance with overall root-mean-square deviations (RMSDs) of 0.3–0.4 kcal mol–1 for the isomerization, ionization, and bond dissociation energies. However, the Gaussian-4 procedures (G4, G4(MP2), and G4(MP2)-6X) showed relatively poor performance with overall RMSDs of 1.3–3.7 kcal mol–1.

scholarly journals Experimental bond dissociation energies of benzylpyridinium thermometer ions determined by threshold-CID and RRKM modeling

2017 ◽  
Vol 417 ◽  
pp. 69-75 ◽  
Author(s):  
David Gatineau ◽  
Antony Memboeuf ◽  
Anne Milet ◽  
Richard B. Cole ◽  
Héloïse Dossmann ◽  
...  
Keyword(s):  
Bond Dissociation Energies ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
Thermometer Ions
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