Rotasjonsspekter

Rotasjonsspekter, also known as rotational spectra, are a type of molecular spectrum that arises from changes in a molecule's rotational energy. Molecules are not rigid bodies; they can rotate in space. This rotation is quantized, meaning that molecules can only exist in specific rotational energy states. When a molecule transitions between these energy states, it can absorb or emit electromagnetic radiation, typically in the microwave or far-infrared regions of the spectrum.

The rotational spectrum of a molecule is characterized by a series of lines, each corresponding to a specific rotational transition. The spacing and intensity of these lines provide valuable information about the molecule's structure, including its bond lengths and bond angles. For linear molecules, the rotational energy levels are given by a simple formula, resulting in a regularly spaced spectrum. For non-linear molecules, the rotational energy levels are more complex, leading to more intricate spectral patterns.

Studying rotational spectra is a powerful tool in chemistry and physics. It allows scientists to identify unknown molecules, determine molecular geometries, and investigate intermolecular interactions. For example, in astronomy, rotational spectroscopy is used to analyze the composition of interstellar clouds and the atmospheres of planets by detecting the spectral signatures of various molecules. The precise measurements obtained from rotational spectra are fundamental to understanding the quantum mechanical nature of molecular motion.