A basis set referring to the set of (nonorthogonal) one-particle functions is used to determine the wave function and to express the unknown molecular orbitals (MOs) using a set of known functions . It can be identified that an unknown MO is a function in endless space defined by a completed basis set by assuming the centre on the nuclei Therefore, selecting a basis set is a critical choice for the calculation, so several points exist to choose the correct basis set for a system. First, a basis set has been appropriate for the structure, making the program faster . For example, a more extensive basis set, such as LanL2DZ, is not an excellent choice for a small organic compound. The other significant point for selecting a basis set is a basis set makes a calculation easy . In other words, a basis set yields chemically meaningful results, and the cost is the other factor affecting selecting a basis set . Besides, all basis sets do not have data about each periodic table element, so when choosing a basis set, it has to have figures about atoms that exist in the structure . In addition, the basis set and the degree of electron correlation impact the accuracy, cost and time. Therefore, the trade-off is the most vital factor for picking a basis set having balanced accuracy, process time, and computational cost. The point that needs to be considered during the selection of the basis set is diffuse functions, which negatively affect the accuracy of the calculation. The basis set must be appropriate to reach convergence regarding electric energy .