Elektronmolnsbilder

Elektronmolnsbilder is a term used in Swedish physics and chemistry to describe visual representations of the electron density surrounding atoms and molecules. They depict where electrons are most likely to be found and are derived from quantum-mechanical descriptions of molecular systems or from experimental electron-density data. The concept reflects the probabilistic nature of electrons in atoms, often contrasted with classical pictures of fixed orbits.

In practice, elektronmolnsbilder can be generated as isosurfaces of the electron density ρ(r), or as color-mapped projections on a molecular surface. They may show total electron density or density corresponding to particular molecular orbitals, and can be complemented by representations of Laplacians or electrostatic potentials. Experimental electron-density maps are obtained from X-ray crystallography or electron diffraction and reconstructed by Fourier methods; computational chemistry produces ρ(r) and orbital plots from ab initio or density-functional theory (DFT) calculations.

Uses include exploring chemical bonding, reaction sites, and charge distribution; in education they help illustrate concepts of valence and bonding in a visual form. Important caveats: electron-density visualizations are models; the appearance can vary with computational method, basis set, and isosurface value; they do not show instantaneous electron positions but probabilistic distributions.

The terminology aligns with the broader concept of molecular orbitals and electron-density analysis common in physical chemistry. Related ideas include electron localization function, molecular electrostatic potential maps, and orbital plots.