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Madhurambal G.,ADM College for women | Ravindran B.,Anjalai Ammal Mahalingam Engineering College | Mariappan M.,RVS College of Engineering and Technology | Mojumdar S.C.,University of New Brunswick
Journal of Thermal Analysis and Calorimetry | Year: 2010

A single crystal of sodium and potassium cinnamates was grown by slow evaporation of methanol solution at room temperature. The effect of metals sodium and potassium on the electronic structure of cinnamic acid was studied. In this research many analytical methods such as FTIR, UV, second harmonic generation (SHG) and TG-DTA were used: The spectroscopic studies lead to conclusions containing the distribution of the electronic charge in molecule, the delocalisation of π electrons and the reactivity of metal complexes. The SHG efficiency is more pronounced in the presence of sodium and potassium dopant in the growth medium. Incorporation of sodium and potassium increase the thermal stability ensuring the suitability of material for possible non-linear optical (NLO) application up to 180 °C. © Akadémiai Kiadó, Budapest, Hungary 2010.


Ramasamy G.,Annamalai University | Bhagavannarayana G.,National Physical Laboratory India | Madhurambal G.,ADM College for women | Meenakshisundaram S.,Annamalai University
Journal of Crystal Growth | Year: 2012

Mixed crystals Zn xMg (1-x)(NH 4) 2(SO 4) 2·6H 2O of the two well-known Tuttons salts Zn(NH 4) 2(SO 4) 2·6H 2O and Mg(NH 4) 2(SO 4) 2·6H 2O were grown with varying molar proportions (x=0.10-0.90) by slow evaporation solution growth technique. The mixed crystal Zn 0.54Mg 0.46(NH 4) 2(SO 4) 2·6H 2O is crystallizing in monoclinic system with space group P2 1/c and cell parameters a=6.2217(4) Å, b=12.5343(7) Å, c=9.2557(6) Å, β=106.912(3)°. The coexistence of zinc and magnesium ions in the mixed crystal was confirmed by inductively coupled plasma (ICP), atomic absorption spectroscopy (AAS) and energy dispersive X-ray spectroscopy (EDS). Compositional dependence of lattice parameters follows Vegards relations. Slight variations are observed in FT-IR and XRD of pure and mixed crystals. Comparison of crystalline perfection as evaluated by high-resolution X-ray diffraction (HRXRD) for mixed crystals of various proportions reveals a reasonably good crystalline perfection for the mixed crystal with nearly equimolar ratio of Zn and Mg. The surface morphology of the mixed crystals changing with composition was studied by scanning electron microscopy (SEM). UV-vis studies reveal that the transparency of the mixed crystals was not much affected. © 2012 Elsevier B.V.


Parthiban S.,Annamalai University | Murali S.,Annamalai University | Madhurambal G.,ADM College for women | Meenakshisundaram S.P.,Annamalai University | Mojumdar S.C.,University of New Brunswick
Journal of Thermal Analysis and Calorimetry | Year: 2010

The influence of doping the transition metal Zn(II) on potassium hydrogen phthalate (KHP) crystals has been studied. A close observation of FT-IR and XRD profiles of doped and undoped samples reveals some minor structural variations. It appears that the crystal undergoes considerable lattice stress as a result of doping the bivalent zinc. Furthermore, the possibility of cation vacancies aroused owing to the substitution of K1+ by Zn2+ could result in a defective crystal system. Energy dispersive spectra reveal the incorporation of Zn(II) in the crystalline matrix of KHP crystals. Differential scanning calorimetry (DSC) and TG-DTA studies reveal the purity of the sample and no decomposition is observed below the melting point. Small quantity additions of Zn(II) enhance the fluorescence intensity of KHP crystals. The doping results in morphological changes and significantly improves the second harmonic generation (SHG) efficiency of the host crystal. © Akadémiai Kiadó, Budapest, Hungary 2010.


Madhurambal G.,ADM College for women | Mariappan M.,EGS Pillay Engineering College | Mojumdar S.C.,University of New Brunswick
Journal of Thermal Analysis and Calorimetry | Year: 2010

A single crystal of urea-thiourea was grown by slow evaporation of aqueous solution at room temperature. The bright and transparent crystals obtained were characterised by TG-DTA, UV and FTIR spectral analyses. A fitting decomposition pattern for the title compound was formulated on the TG curve which shows a two stage mass loss between 200 and 750 °C. DTA curve shows exothermic peaks supporting the formulated decomposition pattern in this temperature range. The UV and FTIR spectra show the characteristic absorption, vibration frequencies due to urea-thiourea zinc chloride crystals. Detailed structural analysis of the compound is under progress. © Akadémiai Kiadó, Budapest, Hungary 2010.


Madhurambal G.,ADM College for women | Mariappan M.,H H the Rajahs College | Hariharan S.,Government of Tamilnadu | Ramasamy P.,SSN College of Engineering | Mojumdar S.C.,Trencin University Of bcek
Journal of Thermal Analysis and Calorimetry | Year: 2013

Mixed crystals of various proportions of zinc magnesium ammonium sulfate were grown by slow evaporation of aqueous solution at room temperature. The bright and transparent crystals obtained were characterized through thermal (TG-DTA) and FTIR spectral analyses. A fitting decomposition pattern for the compound was formulated on the TG curve which shows two stage mass losses between 133 and 478.75 C. DTA curve shows exothermic peaks in this temperature range supporting the formulated decomposition pattern. The FTIR spectra show the vibration frequencies due to the formation of zinc magnesium ammonium sulfate mixed crystals. Detailed structural analysis of the compound is under progress. © 2013 Akadémiai Kiadó, Budapest, Hungary.

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