ABSTRACT
Until now we had assumed that the ions were fixed at their ionic positions and focused on the electronic structure problem, that is we know how to calculate electronic band structure and the total electronic energy using the first-principles approach for a fixed ionic configuration. Now, we will relax the condition that the ions are fixed. We shall see that it is possible to study ion dynamics from the first principles, which, in the most general form, is known as the first-principles molecular dynamics (MD).
