Actually, Raman spectra and infrared radiation along with Density Functional Theory (DFT) are used at the PBE/ 6-31G level including polarization functions to get vibratory properties of silicon phosphide crystal (SiP). Therefore, several physical properties, including energy gaps, tetrahedral angles, and dihedral angles, have been studied. On one hand, all the results showed a decrease in the energy gap with an increase in size that starts from Diamamentan, Tramamentan, Hexamamentan and Octamentan. It then recorded the longest bond at 1.91A in Diamamentan. One the other hand, the tetrahedral angles of Tramamentan and Hexamamentan recorded a value of 109° as well as they are much closer to the ideal value of 109.43°. In addition to Infrared Radiation and Raman spectra were found as a vibratory frequency function

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