| Description |
Measuring thermochemical and kinetic properties of chemical systems has always; been a central theme of chemistry. Knowing these properties assists us in assessing; whether or not a chemical reaction is energetically feasible, efficient, and worthwhile.; Theoretical chemistry has now developed sufficiently to be useful for predicting; molecular properties and the outcomes of reactions that have yet to be observed. This is; relatively straightforward when there are few electrons involved, but calculations become; more inaccurate when treating heavy atoms and molecules with many electrons. In; particularly, transition metals, lanthanides, and actinides, with their partially filled d and f; orbitals, are not easily treated. Moreover, as the atomic number increases, the increasing; charge of the nucleus pulls the electrons closer, causing them to move more quickly.; Relativistic effects begin to emerge, and the Schrödinger equation becomes invalid. The; neglect of relativistic effects, combined with difficulties in correlating the motion of large; numbers of electrons, can lead to significant errors in computational results.; Computational chemists are working to develop more accurate approximations for; modeling chemical behavior, and a particular focus of recent computational work has; been on these more difficult open d and f subshell species. |
