Spectroscopic Characterization and Molecular Dynamics Simulation of Tin Dioxide

Tin dioxide (SnO₂) is a metal oxide with highly symmetric structure at the point that has been studied theoretically and experimentally; however, its band structure is not yet completely understood. The present spectroscopic investigation focuses on rutile SnO₂ in powder form. Raman spectroscopy with laser excitation at 780 nm has been used to characterize the different vibrational modes of SnO₂. Thermal effects associated with the vibrational features in the Raman spectra have been studied in the range 303 – 443 K. We have demonstrated a red-shift in the Raman spectra as the temperature increases for both A_1g (634 cm^-1) and B_2g (775 cm^-1) modes, while the E_g (475 cm^-1) mode exhibited no change. FT-IR spectra have been obtained in order to study the IR-active vibrational modes for tin dioxide: Sn-O stretching vibration (467.4 cm^-1) and Sn-O-Sn asymmetric vibration (569.4 cm^-1). XRD spectra have been recorded to confirm the rutile structure (a=b=4.737Å, c=3.186Å) of tin dioxide. SEM images have provided information regarding surface morphology. Molecular Dynamics simulations have been performed in order to study the various vibrational modes using the LAMMPS software.