Molecular physics

Molecular physics is the study of how molecules behave and what they are made of. Molecules are tiny parts of everything around us, like the water in a glass or the air we breathe. Scientists who study molecular physics look at how these tiny parts move and change.

This area of science overlaps with other subjects like physical chemistry, chemical physics, and quantum chemistry. It is often thought of as a part of atomic, molecular, and optical physics. To understand molecules, scientists use ideas from both old and new physics, called classical and quantum mechanics.

They also study how light and other kinds of energy interact with molecules. Experiments in molecular physics often use special tools, such as spectroscopy and scattering, which help scientists see and measure the tiny actions of molecules. This research helps us learn more about the world and can lead to new technologies and medicines.

Molecular structure

In a molecule, tiny particles called electrons and the centers of atoms, called nuclei, feel similar forces. But the nuclei stay mostly in one place, while the electrons move around a lot. This is because nuclei are much heavier than electrons. Special experiments using neutron scattering have helped scientists learn more about molecules.

Molecular energy levels and spectra

When atoms join to form molecules, some electrons stay close to their original atom, but others spread out around the whole molecule. These spreading electrons decide the energy levels of the molecule. This can be explained using a theory called molecular orbital theory. Molecules have extra energy levels called vibrational and rotational levels. Vibrational levels are about the atoms moving in the molecule, and rotational levels are about the molecule spinning. These energy levels mean molecules can absorb and give off light at different colors and wavelengths.

Experiments

Scientists study molecules to learn about their shapes, sizes, and energy. They use special tools to measure the distances between atoms in molecules. X-ray diffraction helps them see these distances, especially in bigger molecules.

Researchers use molecules to test important scientific ideas and explore new physics. Molecules might help create new technologies for processing information. By studying how energy moves in molecules, scientists learn more about how they behave.