UNDER CONSTRUCTION ! !

Computational Chemistry

Computational chemistry is the use of computers to calculate chemical physical properties. The type of calculation

There are two major types of calculations that PC Spartan uses, semi-empirical and ab initio. Both calculatoins are an approximation of the Hamiltonian. ab initio latin translation is "from the beginning" (or " from first principles").

PC Spartan uses mathematical methods that perform molecular mechanics calculations using SYBYL force field, AM1, PM3, and AM1-SM2 semi-empirical orbital calculations. Although these calculations are not as proficient as ab initio calculations, they are good for fast approximations. A point to note is that for calculations involving transition metals, it is best to use the PM3 algorithm.

Also PC Spartan conducts ab initio calculations using 3-21G(*) and 6-31G(*) basis sets. Ab initio represents first principle calculations, meaning the nature of the calculations are quantum mechanical in origin. Where these calculations are indeed the closest to the actual theoretical value, they are very time consuming. It is often best to use a semi-empirical method, which combines molecular mechanics and ab initio calculations.