What does it mean to do chemistry on a computer? Is it possible to study molecules before examining them in the lab?
This lecture explores how modern computational methods help make the world of atoms and molecules visible and enable us to understand it better. Chemical processes take place on a scale that is hidden from our direct view: electrons move, bonds between atoms form and break, and molecules change their shape—and thus their properties.
With the help of modern theoretical models and powerful computers, researchers can investigate these invisible processes and translate them into clear images, numbers, and predictions.
The lecture provides an accessible introduction to theoretical chemistry and computational chemistry: How do we describe a molecule physically and mathematically? What can a computer predict about chemical bonds, reactions, or spectra—even about the colors of distant stars, nebulae, and planets? And how do computations complement experiments by explaining measurement results, providing new hypotheses, and sometimes even pointing the way to new research?
The role of theoretical calculations in chemistry is also addressed: What do they mean for laboratory experiments? What are the limits of our computer models? The lecture demonstrates that computers do not replace experimentation, but they open up an additional perspective on nature—a perspective in which chemical structures, properties, and changes become clearer.