# What Is Molecular Dynamics?

C.B. Fox

Molecular dynamics is the study of the way that atoms and molecules move. The direct observation of these particles is not always possible, so scientists study molecular dynamics by using mathematical formulas. These formulas are programmed into computers which allow scientists to simulate the motion of various atoms and molecules. Though real particles are not used in the study of molecular dynamics. The results of the simulations are considered to be reasonably accurate.

The study of molecular dynamics is a type of virtual experiment. By studying the behavior of virtual molecules, scientists can make predictions about how real molecules might behave. Though no real molecules are used, the results of these simulated experiments are considered accurate. Adjusting certain parameters in the equations makes the experiments more precise.

Simulations of molecular dynamics are used to make virtual observations of the movement of particles. In a laboratory, it is not always possible or practical to make actual observations of molecular movement, so mathematical simulation and computer modeling are used instead. The benefits of these types of experiments are that motion can be observed for an extended period of time, that it can be observed from closer up, and that conditions, such as extremes in pressure or temperature which are not practical in the lab, can be simulated.

Computers are able to display a visual representation of the movement of atoms and molecules by solving mathematical equations. The equations are based on Newton's laws and can accurately predict the motion of most atoms and molecules. Simulation programs use the equations to represent the forces that act on the particles and the movement of the atoms in three dimensional space. It is also possible to track the movement of an atom or molecule over time using these formulas.

Molecular dynamics can also be used to observe the relationships between atoms and molecules. The simulation programs track the molecular bonds that are formed and broken and adjust the equations accordingly. Though the equations used are based on Newton's laws of motion, in most cases they can be applied to the motion of very small particles. Occasionally, the laws that govern the movement of quantum particles must be used in the molecular dynamics equations to correctly describe particle motion.