If you follow this course in sync with the live classes (September-December), then this chapter is your main content for week 8 of the fall term (see the due dates).
Going thoroughly through this chapter, will take you about 2 hours (including the time spent in the corresponding hands-on section let’s play).
If you have a general science background, there is no doubt you have some mental image of a chemical bond. It can be an intuitive or a sophisticated image, but at least the word chemical bond has a meaning for you. In this chapter, we will examine how DFT can increase your insight in the chemical bonds that are present in a given crystal. You will use for that purpose information based on total energies — well known to you by now, see previous chapters — as well as four-dimensional information available in electron density difference plots. How to compute the latter with Quantum Espresso code is explained in the hands-on section ‘let’s play’).