Hirshfeldpartíció

Hirshfeldpartíció, also known as Hirshfeld partitioning, is a method for dividing the electron density of a molecular system into atomic contributions. Developed by Warren Hirshfeld, this technique aims to assign each point in space to the atom whose electron density is dominant in that region. The partition is dynamic, meaning it depends on the molecular environment.

The core idea of Hirshfeld partitioning is to compare the electron density of a free atom to the total electron density of the molecule at any given point. A weight function is used to determine which atom's density is closer to the molecular density at that point. This weight is calculated based on the ratio of the free atom's electron density to the sum of the electron densities of all free atoms in the molecule, evaluated at that specific point in space.

This partitioning scheme is particularly useful in understanding charge transfer and electrostatic potentials within molecules. By assigning electron density to individual atoms, Hirshfeld partitioning allows for the calculation of atomic charges and dipoles that are environmentally dependent. This contrasts with other partitioning schemes that might use fixed atomic radii or basis set expansions. The method has found applications in various areas of chemistry, including crystal engineering, intermolecular interactions, and the analysis of electronic structure. It provides a way to interpret molecular properties in terms of atomic contributions, even in complex chemical environments.