Hemanthkumar, G N and Parthasarathy, G and Chakradhar, R P S and Omkaram, I and Rao, J Lakshmana and Ratnakaram, Y C (2009) Electron paramagnetic resonance studies on clinochlore from Longitudinal Valley area, northeastern Taiwan. Physics and Chemistry of Minerals, 36 (8). pp. 447-453. ISSN 0342-1791

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Abstract

A natural sample of clinochlore from the Longitudinal Valley area of northeastern Taiwan has been characterized by using the powder X-ray diffraction (XRD), differential thermal analysis and electron paramagnetic resonance (EPR) spectroscopic techniques. The lattice parameters of the monoclinic (IIb) clinochlore with the composition (Mg(2.988) Al(1.196) Fe(1.6845) Mn(0.026))(5.8945) (Si(2.559) Al(1.441))(4) O(10) (OH)(8) have been calculated from the powder XRD data and are found to be a = 5.347 , b = 9.223 , c = 14.250 , beta = 97.2A degrees and Z = 2. The thermal behaviour of the sample showed the typical behaviour of clinochlore with a hydroxyl content of 12.5 wt%. The EPR spectrum at room temperature exhibits two resonance signals centred at g a parts per thousand 2.0 and g a parts per thousand 8.0. The signal at g a parts per thousand 2.0 shows a six-line hyperfine structure which is a characteristic of Mn(2+) ions in octahedral symmetry. The resonance signal at g a parts per thousand 8.0 is a characteristic of Fe(3+) ions. The EPR spectra have also been recorded at different temperatures (123-295 K). The population of spin levels (N) has been calculated for g a parts per thousand 2.0 and g a parts per thousand 8.0 resonance signals. It is observed that N increases with decreasing temperature. From EPR spectra, the spin-Hamiltonian parameters have been evaluated. The zero-field splitting parameter (D) is found to be temperature dependent. The peak-to-peak width of the g a parts per thousand 8.0 resonance signal is found to increase with decrease in temperature.

Item Type:	Article
Uncontrolled Keywords:	Clinochlore; Mn(2+); Powder XRD; Electron paramagnetic resonance (EPR); Taiwan
Subjects:	Microstructure and Characterization
Divisions:	Glass
Depositing User:	Bidhan Chaudhuri
Date Deposited:	27 Feb 2012 08:14
Last Modified:	27 Feb 2012 08:14
URI:	http://cgcri.csircentral.net/id/eprint/1025

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