PDA

View Full Version : DFT algorithm


Karrar
Aug31-10, 01:57 AM
from my reading to DFT I constructed this algorithm

V ex....>\rho ....\varphi.....SCF....new\varphi>>>new\rho ....energy

what your opinion in this algorithm ... is lost to some thing ?

and i need to some one tell me is density come from wave function or from V-external ?

alxm
Aug31-10, 06:18 AM
I don't see how that constitutes an algorithm (feel free to prove me wrong by writing an implementation).

Charitably interpreting that as a general statement to the effect of "You can use an SCF-like procedure to calculate the density", then that's true. It's also what everyone's been doing for the last 40 years, solving the Kohn-Sham equations. The difficulty in developing the Roothaan-Hall and Kohn-Sham equations wasn't finding an iterative procedure to solve them. They already knew how to solve eigenvalue problems. The difficulty was reformulating the problem into a generalized eigenvalue problem. You're approaching the problem backwards.

Karrar
Aug31-10, 11:50 AM
I construct this scheme for understanding DFT not for treatment something ... so I have Problem with density equation ... what the equation that include the Vex with electron density ... this my Problem ... thanks alxm for interest