molekylærmekanik

Molekylærmekanik, or molecular mechanics, is a computational chemistry method used to simulate the structure and properties of molecules. It treats atoms as spheres and bonds as springs, calculating the total energy of a molecule based on these simplified representations. This energy is determined by a force field, which is a set of mathematical functions and parameters that describe the potential energy of the system as a function of the atomic positions.

The core idea behind molecular mechanics is to approximate the potential energy surface of a molecule. Instead of solving the complex Schrödinger equation as in quantum mechanics, molecular mechanics uses empirical relationships derived from experimental data or higher-level calculations. These relationships define terms for bond stretching and bending, torsional angles, van der Waals interactions, and electrostatic interactions between atoms.

The result of a molecular mechanics calculation is typically the equilibrium geometry of a molecule, its vibrational frequencies, and its conformational preferences. It is particularly useful for studying large molecules like proteins and nucleic acids, where full quantum mechanical calculations would be computationally prohibitive. Common applications include protein folding simulations, drug design, and the study of molecular recognition. While molecular mechanics is faster and less computationally demanding than quantum mechanics, its accuracy is limited by the quality of the force field used.