A relationship between experimentally determined pKas and molecular surface ionization energies for some azines and azoles

1991 ◽  
Vol 56 (8) ◽  
pp. 2934-2936 ◽  
Author(s):  
Tore Brinck ◽  
Jane S. Murray ◽  
Peter Politzer ◽  
Robert E. Carter
Keyword(s):  
Molecular Surface ◽  
Surface Ionization ◽  
Ionization Energies

Calculated electrostatic potentials and local surface ionization energies of para-substituted anilines as measures of substituent effects

1992 ◽  
Vol 70 (8) ◽  
pp. 2209-2214 ◽  
Author(s):  
Markus Haeberlein ◽  
Jane S. Murray ◽  
Tore Brinck ◽  
Peter Politzer
Keyword(s):  
Substituent Effects ◽  
Correlation Coefficients ◽  
Electrostatic Potentials ◽  
Surface Ionization ◽  
Local Surface ◽  
Substituted Anilines ◽  
Amine Nitrogen ◽  
Ionization Energies ◽  
Linear Relationships ◽  
Self Consistent Field

Using an abinitio self-consistent-field molecular orbital approach, we computed 3-21G//STO-3G* and STO-5G//STO-3G* electrostatic potentials and average local ionization energies for 17 para-substituted anilines. Our results demonstrate that the most negative potentials (Vmin) and the local surface ionization energy minima (ĪS,min) associated with the amine nitrogen lone pairs are highly sensitive indicators of the electron-donating and electron-attracting tendencies of the para substituents. We find excellent linear relationships between the 3-21G//STO-3G* amine nitrogen Vmin and ĪS,min and the σp0 Hammett constants of the substituent X; the correlation coefficients are 0.99. Correlations of slightly lesser quality are shown to exist between Vmin, ĪS,min, and σp−, σp, and pKa. Estimates of previously unknown σp0 and pKa values are given. The presence of ring carbon ĪS,minmeta to the substituent X also provides a predictive capability for determining σm values.

Ionization energies of hypervalent Li2F, Li2Cl and Na2Cl molecules obtained by surface ionization electron impact neutralization mass spectrometry

2003 ◽  
Vol 17 (3) ◽  
pp. 212-214 ◽  
Author(s):  
Olivera M. Ne?kovi? ◽  
Miomir V. Veljkovi? ◽  
Suzana R. Veli?kovi? ◽  
Ljubica T. Petkovska ◽  
Aleksandra A. Peri?-Gruji?
Keyword(s):  
Mass Spectrometry ◽  
Electron Impact ◽  
Surface Ionization ◽  
Ionization Energies ◽  
Ionization Electron

Surface ionization engine development

1966 ◽  
Author(s):  
M. ERNSTENE ◽  
A. FORRESTER
Keyword(s):  
Surface Ionization ◽  
Engine Development
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