where, lx, ly and lz are the parameters that provide the important information about the orbital. The sum of the parameters, i.e., lx + ly + lz = L is analogous to angular momentum for the atom. The varying value of L corresponds to the different shapes of orbitals, for example, s-type (L=0), p-type (L=1), d-type (L=2) and f-type (L=3). The Gaussian function mentioned in Equation ( ) is called the primitive Gaussian function. The group of the several primitive Gaussian functions provide the new one-Gaussian function which is known as "contracted Gaussian function", given as below;