Atomistic Modeling

We study the dynamics of spins, atoms, molecules and materials on different length and time scales. The spin is used to study magnetics and superconductivity while the atom is used to study various aspects of material dynamics. For many material dynamics simulations it is sufficient to use the atoms as the smallest building blocks, not the electron as we do in electronic structure theory. This modelling theory is usually called Molecular Dynamics (MD) - more specifically Molecular Mechanics based Molecular Dynamics (MM-MD). MD is used to study the dynamics in gases, liquids and solutions, and the solid state, and it includes effects from vibration-, electrostatic- and dispersion-interactions. These interactions are defined through the so called 'force field', which typically is tailored for the system at hand using properties from experimental measurements or density functional theory simulations. It is a theory that describes van der Waals interactions very accurately at very affordable computational cost, and can be used to model millions of atoms with a time-step in the femtosecond scale - resulting in dynamical information typically over several nanoseconds. MM-MD is in its general form not suited to study dynamical processes where bonds are broken and formed, for which ab initio molecular dynamics is needed (ai-MD).