The Hollow Spherical Silica Molecule (SiO2)20(H2O)10: Theoretical Calculations of the IR spectrum

The IR spectrum of hollow spherical molecule (SiO2)20(H2O)10 have been calculated within harmonic approximation using density functional theory method (exchange-correlation functional B3LYP and basis set 6-31G (d, p)) and an assignment have been made of the frequencies to the forms of vibrations. It has been shown that the theoretically calculated spectrum of molecule (SiO2)20(H2O)10 is consistent with the experimental spectra of nanospheres, so the molecule (SiO2)20(H2O)10 and its higher homologues can be used in quantum-chemical calculations of the properties of synthesized hollow nanospheres (d ≈ 290 nm).

Comparison Between the Phase Transition of Physically Confined Cyclohexane and 1-Decanol inside Nano Porous Silica

ABSTRACTThe thickness of non-freezing interfacial 1-decanol molecules has been estimated to be 1.44 ± 0.07 nm. This is smaller than what is estimated for cyclohexane, 2.25 ± 0.14nm. Furthermore, these interfacial molecules have higher density than corresponding bulk cyclohexane and 1-decanol, respectively. However, the change in density of the interfacial molecules is more significant in the case of cyclohexane than 1-decanol. This suggests that the cyclohexane molecules near the walls of the pore are more tightly packed than 1-decanol molecules. Presumably, this is due to the difference in size and shape of the molecules. Cyclohexane, a more spherical molecule, can easily be packed in smaller pores than the longer 1-decanol.