Spectroscopic studies of Cr{sup 3+} ions doped in poly(vinylalcohol) complexed polyethylene glycol polymer films

Journal Article · Fri May 15 00:00:00 EDT 2015 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4915459· OSTI ID:22391769

Rao, T. Rajavardhana; Brahmam, K. Veera ^[1]

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1. Advanced Systems Laboratory, Kanchanbagh, Hyderabad 500 058 (India)

Polymer films of Poly(vinylalcohol) (PVA) complexed with Polyethylene glycol (PEG) with different dopant concentrations of Cr{sup 3+} ions are prepared by solution cast technique. Electron paramagnetic resonance (EPR), Optical absorption and FT-IR studies have been carried out on the polymer films. The EPR spectra of the entire samples exhibit resonance signal at g ≈1.97 which is attributed to the isolated Cr{sup 3+} pairs. The temperature variation EPR studies show that the population of spin-levels participating in the resonance decreases with an increase in temperature, which is in accordance with the Boltzmann Law. The paramagnetic susceptibilities (X) have been calculated from the EPR data at different temperatures. The linewidth of the g ≈1.97 resonance signal has been found to be decreasing with an increase in temperature, which confirms the pairing mechanism between Cr{sup 3+} ions. The Optical absorption spectrum of chromium ions in (PVA+PEG) polymer films exhibits three bands, corresponding to the d-d transitions {sup 4}A{sub 2g}(F)→{sup 4}T{sub 1g}(F), {sup 4}A{sub 2g}(F)→{sup 4}T{sub 2g}(F) and {sup 4}A{sub 2g}(F)→{sup 2}T{sub 1g}(G), in the order of decreasing energy. The crystal field parameter Dq and the Racah interelectronic repulsion parameters B and C have been evaluated. From the ultraviolet absorption edges, Optical band gap (E{sub opt}) and Urbach (ΔE) energies are evaluated. FT-IR spectrum exhibits few bands which are attributed to O-H, CH, C=C and C=O groups of stretching and bending vibrations.

• OSTI ID: 22391769
• Journal Information: AIP Conference Proceedings, Vol. 1661, Issue 1; Conference: ICCMP 2014: International Conference on Condensed Matter Physics 2014, Shimla (India), 4-6 Nov 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTRA
BENDING
CHROMIUM IONS
CONCENTRATION RATIO
CRYSTAL FIELD
DOPED MATERIALS
ELECTRON SPIN RESONANCE
FILMS
FOURIER TRANSFORMATION
INFRARED SPECTRA
PARAMAGNETISM
POLYETHYLENE GLYCOLS
PVA
SPIN
ULTRAVIOLET RADIATION