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Ab initio study of the proton affinity of a number of ortho‐substituted pyridines
Author(s) -
Martin J. M. L.,
François J. P.,
Gijbels R.
Publication year - 1989
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540100308
Subject(s) - basis set , dipole , computational chemistry , basis (linear algebra) , chemistry , electronic correlation , proton , electron affinity (data page) , ab initio , proton affinity , superposition principle , moment (physics) , ionization , ionization energy , heteroatom , atomic physics , mathematics , electron , physics , quantum mechanics , density functional theory , molecule , geometry , ring (chemistry) , ion , organic chemistry , protonation
The proton affinity, dipole moment, and first vertical ionization potential of a number of ortho‐mono‐substituted pyridines are computed at the restricted Hartree‐Fock level, using a number of different basis sets. Some approximations concerning the geometry, the force constants, and the basis set superposition error are introduced. The effect of both the basis set and the approximations is investigated systematically. Two nonstandard basis sets, 4‐31G(*) and 4‐31+G(*), in which polarization functions are only applied to heteroatoms, are defined. A qualitative explanation for the effects of electron correlation on the proton affinity is given and underbuilt with the results of some MP2 calculations. While accuracy is maintained, computational cost is reduced very substantially.