Premium
Charge separation in a heteronuclear molecule: II, effects on calculated molecular properties
Author(s) -
Corrington Joyce H.,
Cusachs Louis Chopin
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560030724
Subject(s) - heteronuclear molecule , hamiltonian (control theory) , diagonal , charge (physics) , atom (system on chip) , atomic physics , chemistry , molecule , effective nuclear charge , molecular physics , electron , physics , computational chemistry , quantum mechanics , mathematical optimization , geometry , mathematics , computer science , embedded system
Three methods of approximating the diagonal elements of the one‐electron Hamiltonian matrix for semiempirical MO calculations are discussed: employing the orbital energy of the free atom, correcting it for charge migration (net charge), and also correcting it for neighbor atom potentials. An analytic method for estimating the neighbor atom potentials is suggested, and it is employed to estimate the change in the diagonal Hamiltonian elements due to neighboring atoms. The results from calculating molecular properties employing the three approximations for the H ii elements are presented. It is found that charge distribution is quite sensitive to the approximation employed, and that in order to achieve good predictions of molecular properties it is necessary to take into account the electrostatic potentials due to neighboring atoms.