El-Kabbany, F., S. Taha, and M. Hafeza, "Thermal and spectroscopic properties of the nano-system (ZnO(1−x)SiO2(x))", Journal of Molecular Structure, vol. 1111, pp. 33–45, 2016. Abstract

Structural and thermal properties of the investigated nano-matrix ZnO(1−x)SiO2(x) samples were characterized by various techniques such as X-ray analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential thermal analysis (DTA). IR spectroscopic analysis in the frequency range 400–4000 cm−1 is used here to investigate the new nano-system at room temperature. The variation of enthalpy (ΔH) with the concentration of SiO2 nanoparticles for the five systems of the ZnO(1−x)SiO2(x) matrix is determined. Seven different fundamental modes have been investigated. All of the vibrations of the investigated nano-system (ZnO(1−x)SiO2(x)) were found to be 449 cm−1, 469 cm−1, 798 cm−1, 959 cm−1, 1096 cm−1, 1630 cm−1 and 3447 cm−1 correspond to normal vibrations of stretching mode of ZnO, Si – O – Si or O – Si – O bending mode, Si – O – Si symmetric stretching, vibrational mode of Si–O – Zn, Si – O – Si asymmetric stretching, bending vibration mode of adsorbed water and stretching vibration of OH group respectively in which the variations strongly support the variation of ZnO and SiO2 nanoparticles concentration in the studied matrix. Measurements and interpretation of IR spectra as a function of ZnO and SiO2 nanoparticles concentration is reported.

El-Kabbany, F., S. Taha, M. Hafez, and A. N. R. Aziz, "Infrared study and phase transformation of the new lithium–diphenyl carbazide complex (LiDPC)", Journal of Molecular Structure, vol. 1092, pp. 113 - 121, 2015. Website
El-Kabbany, F., S. Taha, and M. Hafez, "A study of the phase transition of reheated diphenyl carbazide (DPC) by using UV spectroscopy.", Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, vol. 128, pp. 481-8, 2014 Jul 15. Abstract

Phase transition phenomenon in reheated diphenyl carbazide (DPC) is studied here using UV spectroscopy. The optical band gap for reheated DPC is obtained by measuring the optical diffused reflectance (DR) and equals to 3.55 eV. Also, the optical band gap is calculated using UV technique and equals to 3.548 eV. The absorbance of reheated DPC is studied at some selected temperatures in order to check the presence of phase transitions at 90°C and 125°C. According to the present work, the band gaps are calculated at 80°C, 110°C and 130°C and equal to 3.548 eV. But at 100°C, the optical band gap has changed to 4.139 eV. It was found that each phase of reheated DPC belongs to a certain definite crystal structure. The presence of the phase transitions are checked and confirmed by scanning electron microscopy (SEM). The structural properties and morphology of reheated diphenyl carbazide are investigated by SEM. The SEM images are taken at some selected temperatures to confirm the presence of phase transitions.

El-Kabbany, F., S. Taha, and M. Hafez, "IR spectroscopic analysis of the new organic silver complex C13H13N4OAg", Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 111, pp. 252–259, 2013. Abstract

IR analysis in the frequency range 400–4000 cm−1 is used here to investigate the changes in different modes of thermally treated new metal complex (diphenyl carbazide silver complex DPCAg, C13H13N4OAg) during the glass transition at 91 °C and the high temperature phase transition at 167 °C. These two phase transitions in this new metal compound are studied here by detecting the changes in some IR spectroscopic parameters (e.g., mode shift, band contour, peak height and peak intensity) during the elevation of temperature. All of the vibrations of DPCAg were found to be due to ionic fundamentals 3311 cm−1, 3097 cm−1, 3052 cm−1, 1677 cm−1, 1602 cm−1, 1492 cm−1, 1306 cm−1, 1252 cm−1, 887 cm−1 and 755 cm−1. The results obtained can be considered as the first spectroscopic analysis of this new metal complex. These results strongly confirmed that the thermally treated DPCAg transverse a glass transition at 91 °C and a high temperature phase transition at 167 °C. Anomalous spectroscopic changes near the glass transition temperature Tg could be recorded. A temperature dependence of peak intensity of the two modes 810 cm−1 and 3440 cm−1 could be observed beyond Tg. Also, the high temperature phase modification at 167 °C showed anomalous change in the spectroscopic parameters before and after the phase transition process. A proposed silver position in the new silver complex DPCAg has been presented.