| Popis: |
The spatial three-dimensional structure of molecules in atomic resolution represents the most important information, which decides about chemical and physical properties of substances. Such key information is offered only by a few experimental methods. Theory offers a much less expensive alternative way by minimizing electronic energy as a function of coordinates of the nuclei. For large molecules, however, some approximate expressions for the electronic energy have to be used (known as force fields). In spite of their approximate character they provide a lot of reliable structural data of great importance. |
