
TY  - JOUR
A1  - Brown, RD 
A1  - Heffernan, ML 
T1  - The 'Variable Electronegativity ' Method. II. Pyrrole
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1959
VL  - 12
IS  - 3
SP  - 319
EP  - 329
KW  - 
UR  - https://doi.org/10.1071/CH9590319 
N2  - The properties of the &#960;-electron system in pyrrole have been studied by a &quot; variable electronegativity &quot; self-consistent field molecular-orbital method and the results compared with those obtained by the conventional SCF procedure. The &#960;-electron distribution calculated by the conventional SCF procedure cannot be satisfactorily reconciled with the observed dipole moment, but the distribution calculated by the VESCF method leads to a predicted dipole moment in good agreement with observation. Polarization of &#963;-bonds makes a negligible contribution to the dipole moment.Derivation of the coulomb parameters for the simple Hückel molecular-orbital method from the VESCF results is considered and the factors responsible for auxiliary inductive effects are discussed. The &#960;-electron ionization potential and the positions of the lowest excited states of pyrrole have been calculated by the VE method. 
ER  -

