Basic Quantum Mechanics for Density Functional Theory
This post is basic quantum mechanics tutorial for studying density functional theory. As you know, density functional theory is to solve Schrodinger equation. And here is the first step to get to the Schrodinger equation. Maybe almost every science or engineering student is very familiar with above picture, which is experimental observation of photon energy of light by Einstein. Photon has a energy only if their energy is bigger than work function W. E = hv - W , h: Plank constant, v: frequency This is closely related to induce operators that consist of Schrodinger equation. and we can re-describe above equation as using modified Plank constant. The reason why energy equation by modified Plank constant is defined is that this representation is much more convenient when we are developing some equations or theories. If you study more and more, you will realize naturally.