08-CompChem7-2 - Chemistry 6440 / 7440 (B. Schlegel, Wayne...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Chemistry 6440 / 7440 (B. Schlegel, Wayne State) Density Functional Theory
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Electronic Energy Components Total electronic energy can be partitioned E = E T + E NE +E J + E X +E C E T = kinetic energy of the electrons E NE = Coulomb attraction energy between electrons and nuclei E J = Coulomb repulsion energy between electrons E X = Exchange energy, a correction for the self-repulsions of electrons E C = Correlation energy between the motions of electrons with different spins • E T , E NE J are largest contributors to E • E X > E C
Background image of page 2
Electron Correlation In the Hartree-Fock approximation, each electron sees the average density (aka mean field) of all of the other electrons Two electrons cannot be in the same place at the same time Electrons must move two avoid each other, i.e. their motion is correlated Types of electron correlation Dynamical Non-dynamical The difference between the exact energy and the Hartree-Fock energy is the correlation energy for a particular basis set.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Resources Scuseria and Staroverov,Theory and Applications of Computational Chemistry The First Forty Years, Chapter 24, 2005 . Kohn Nobel Lecture: Reviews of Modern Physics,71,1253, 1999 . Foresman and Frisch, Exploring Chemistry with Electronic Structure Methods, Appendix A Burke’s DFT book (work in progress): http://dft.rutgers.edu/kieron/beta/b4.pdf Parr and Yang, Density Functional Theory, Oxford University Press, 1989 .
Background image of page 4
The wave function itself is essentially uninterpertable. Reduce problem size: Wave functions for N - electron systems contain 4 N coordinates. Wave function based methods quickly become intractable for large systems, even with continued improvement in computing power, due to the coupled motion of the electrons. A desire to work with some physical observable
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 25

08-CompChem7-2 - Chemistry 6440 / 7440 (B. Schlegel, Wayne...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online