Photoacoustic spectrum of samarium phthalocyanine powder

George, Nibu A.; Jyotsna, R.; Lee, S. Thomas; Aneeshkumar, B.; Thomas, Jayan; Nampoori, V. P. N.; Radhakrishnan, P.

doi:10.1016/j.optmat.2004.05.008

Cited by 5 publications

(3 citation statements)

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“…p* transition from the HOMO (highest occupied molecular orbital) to the LUMO (lowest unoccupied molecular orbital) of the Pc 2À ring. The Q y band at 690 nm is attributed to that of the neutral dimer form (George et al, 2005;Khatib et al, 1988;Kumar et al, 2001). The broad B band in the 300-400 nm is attributed to the deeper p levels !…”

Section: Resultsmentioning

confidence: 99%

Optical amine sensor based on metallophthalocyanine

Liu

2007

Journal of the Chinese Institute of Chemical Engineers

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Section: Resultsmentioning

confidence: 99%

Optical amine sensor based on metallophthalocyanine

Liu

2007

Journal of the Chinese Institute of Chemical Engineers

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“…25,26 The reason for the scarcity of studies about the optical properties may be due to the fact that the Li x Mn 2 O 4 powders are optically opaque and most of the optical absorption spectroscopy studies rely on the transmission technique. Hence, we have employed photoacoustic spectroscopy ͑PAS͒ in determining the optical absorption spectrum of Li x Mn 2 O 4 due to its unique advantage of directly measuring the amount of light absorbed by a material [27][28][29][30][31][32] and its zero-base-line advantage, which means signals are generated only if there is an optical absorption event. Moreover, scattered light, which presents such a serious problem in conventional spectroscopic techniques, presents less difficulty in PAS and can be solved by making necessary corrections.…”

Section: Introductionmentioning

confidence: 99%

Effect of lithium concentration on the thermal and optical properties ofLixMn2O4by photoacoustic measurements

et al. 2007

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In the present work, pellets of Li x Mn 2 O 4 polycrystalline powder samples with x = 0.8, 0.9, 1.0, 1.1, and 1.2 are analyzed to understand the effect of lithium concentration on the thermal and optical properties, and the electronic structure of Li x Mn 2 O 4 predicted in an earlier work using full-potential linear muffin-tin orbital ͑FP-LMTO͒ method is experimentally verified. The experimental tool used for the determination of the thermal and optical properties is the well-known photoacoustic technique. The variation of thermal diffusivity with changing x values in Li x Mn 2 O 4 is extensively studied to explain the influence of lithium concentration on the thermal properties, and has been correlated with the structural asymmetry and defects in Li x Mn 2 O 4 . The optical absorption spectrum, being the signature of the electronic structure of materials, is recorded in the visible range ͑350-800 nm͒. Six prominent absorption peaks associated with the O 2p-Mn t 2g , O 2p-Mn e g , and Mn t 2g -Mn e g band transitions for Li x Mn 2 O 4 , with x ഛ 1, are observed experimentally, substantiating the electronic structure predicted by the FP-LMTO method. However, it is observed that there are more absorption peaks in the case of Li 1.1 Mn 2 O 4 and Li 1.2 Mn 2 O 4 , which is attributed to the structural distortion from pure cubic spinel structure to a mixture of spinel and tetragonal structures, which is verified by the x-ray diffraction spectra.

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“…The reason for the scarcity of studies on the optical properties may be that the LiMn 2 O 4 powders are optically opaque and most of the optical absorption spectroscopy studies rely on the transmission technique [14]. However, photoacoustic spectroscopy (PAS) is a powerful tool in obtaining the optical absorption spectrum of any light absorbing material, be it gas, liquid or any type of solid or semisolid material, be it crystalline, powder, amorphous, smear, gel, etc [15][16][17][18]…”

Section: Introductionmentioning

confidence: 99%

Evidence of band structure modification due to Jahn–Teller distortion in Li_xMn₂O₄by photoacoustic spectroscopy

Lee¹,

Raveendranath²,

Tomy³

et al. 2007

J. Phys. D: Appl. Phys.

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Photoacoustic (PA) spectra of Li0.9Mn2O4, LiMn2O4 and Li1.1Mn2O4 at two temperatures, 298 K and 280 K which are, respectively, above and below the Jahn–Teller phase transition temperature, 290 K, are determined. The spectra of LiMn2O4 and Li1.1Mn2O4 below the transition temperature are found to be significantly different from their respective spectra above the transition temperature. However, the PA spectra of Li0.9Mn2O4 at both these temperatures show only a minor difference between each other compared with the changes occurring in LiMn2O4 and Li1.1Mn2O4. These effects are explained on the basis of the predominant JT tetragonal distortion in cubic LixMn2O4 with a high Li content, which brings forth a modification in their electronic structure.

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Photoacoustic spectrum of samarium phthalocyanine powder

Cited by 5 publications

References 10 publications

Optical amine sensor based on metallophthalocyanine

Optical amine sensor based on metallophthalocyanine

Effect of lithium concentration on the thermal and optical properties ofLixMn2O4by photoacoustic measurements

Evidence of band structure modification due to Jahn–Teller distortion in Li_xMn₂O₄by photoacoustic spectroscopy

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Photoacoustic spectrum of samarium phthalocyanine powder

Cited by 5 publications

References 10 publications

Optical amine sensor based on metallophthalocyanine

Optical amine sensor based on metallophthalocyanine

Effect of lithium concentration on the thermal and optical properties ofLixMn2O4by photoacoustic measurements

Evidence of band structure modification due to Jahn–Teller distortion in LixMn2O4by photoacoustic spectroscopy

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Evidence of band structure modification due to Jahn–Teller distortion in Li_xMn₂O₄by photoacoustic spectroscopy