Abstract
Abstract Since the atomic point charges came into wide use as the electrostatic part of modern molecular force fields, dozens of empirical and semiempirical charge calculation methods were developed over the last few decades. Many of them employ electronegativity equalization, one of the DFT cornerstone principles. We show that algebraically all known electronegativity equalization schemes can be divided into two different groups with respect to the underlying mathematical formalism and the degree to which electronegativity is equalized. Methods of the first group are based on the generalized hardness matrix formalism and provide complete electronegativity equalization, whereas another group of methods invokes the Laplacian matrix formalism and results in a redistribution of electronegativity rather than complete equalization. A new principle of electronegativity relaxation is introduced. Electronegativity identified with electrical potential is viewed as a harmonic function satisfying a discrete Laplace equation with Dirichlet boundary conditions. A Markov chain formalism for solving such equations is developed. Some numerical results of chemical interest are discussed. Application of atomic charges in different areas of molecular modeling is overviewed.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.