Materials Science

This paper presents preparation, characterization and humidity sensing properties of SnO2 thin films. In the present investigations, the nanocrystalline SnO2 thin films were prepared by spray pyrolysis technique. These films were characterized by X-ray diffraction (XRD) measurements, and scanning electron microscopy (SEM).The humidity sensing properties of prepared SnO2 thin films were investigated in lab-built sensing unit. The prepared SnO2 thin films show excellent response to humidity changes with fast response and recovery time.

Nickel oxide nanoparticles were synthesized by co-precipitation method at different solution temperatures 37?C,50? C and 70?C and calcined at 700?C.The crystalline structure of NiO NPs were studied by X-ray diffractometer ( XRD).The results confirmed the cubic structure of Nickel oxide nanoparticles and the solution temperature has no effect on crystal structure .The optical properties of the NiO samples were characterized by FT-IR,UV-VIS and PL and the morphology by scanning electron microscopy. Cyclic voltammetry characterization was carried out to study the qualitative information about the potentials at which electrochemical reactions occur.

The vibrational spectra of 5-bromo-2-chlorotoluene (5B2CT) have been obtained by density functional theory (DFT) calculations. Normal coordinate analysis has been carried out to support the vibrational analysis. The results were compared with the experimental values. With the help of scaling procedures, the observed FTIR and FT Raman vibrational frequencies were analysed and compared with the theoretically predicted vibrational spectra. The assignments of bands to various normal modes of the molecules were also carried out. The Electrostatic potential (ESP) of the title molecule were also performed. Further, density functional theory (DFT) combined with quantum chemical calculations to determine the first-order hyperpolarizability. The calculated HOMO and LUMO energies shows that charge transfer occur within the molecule. Electronic excitation energies, oscillator strength and nature of the respective excited states were calculated by the closed-shell singlet calculation method were also calculated for the molecule.