Computational tools small molecule

These crude calculations which assist the spectroscopist in his interpretation have been possible for some time and are increasingly used almost as an experimental tool. Recently, however, the power of electronic computers has advanced to the stage where, for small molecules, wavefunctions of a very accurate nature can be calculated. For very good wavefunctions, energies and, more especially, other expectation values can be computed very accurately. Indeed in some instances spectroscopic constants can now be computed to greater precision than they can be measured. 

---