Chemistry is traditionally an experimental science.
Such computer calculations are used within our group to determine the structures of molecules and to help understand how molecules react with one another. The procedure employed is called ab initio molecular orbital theory, the term ab initio signifying that the calculations are carried out from first principles using the laws of quantum mechanics. No experimental data other than values of fundamental physical constants are used. An important feature is that the calculations can be carried out as readily for reactive or hazardous species as for normal, stable molecules. They are therefore particularly useful in cases where experimental studies might be difficult or impossible.