In the realm of computational chemistry and quantum mechanics, Slater-type orbitals (STOs) and Gaussian-type orbitals (GTOs) are two fundamental mathematical constructs employed to describe the wave functions of electrons in atoms and molecules. Within these categories, the Slater-type orbital methods, particularly SPDF (Slater-type p orbitals for d functions) and DADF (Diffuse Augmented Density Functional), have garnered significant attention. This paper aims to elucidate the differences between SPDF and DADF, focusing on their theoretical underpinnings, applications, and implications in computational chemistry.