Fluorescence Excitation and Emission Spectroscopy on Single MEH-PPV Chains at Low Temperature

ABSTRACTWe have investigated color centers in MgO-doped polycrystalline alumina (PCA) using absorption, excitation, and emission spectroscopy. Most of the color centers that were reported in earlier studies of the crystalline material have been observed to be present in the polycrystalline material. The absorption spectral features observed in the PCA are attributed to various color centers; however, they are not sufficiently resolved to make unique assignments. Suitable combinations of excitation and emission spectroscopy and also measurements at low temperature were therefore used to identify most of the color centers in this material.Among the numerous color centers that we have identified in PCA are variations of electron centers including F, F+, F2+, F22+ and F+-Mg ((Vo•-MgAl')x). The most prominent oxygen vacancy related defect observed at room temperature was the F+-Mg center, with absorption bands located at 217 and 249 nm, and an emission band at 303 nm. This center can be thought of as being formed by association of an F+ center with a Mg defect. The single crystal sapphire samples containing no Mg show only F+ (Vo•) centers with 230 and 257 nm absorption bands, and a 328 nm emission band.Low temperature (22 K) fluorescence excitation measurements of PCA led to emission from F22+center at 467 nm. Additionally, there is evidence that the observed 368 nm emission band could be attributed to the zero-phonon line associated with the F2+center.

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Spectroanalytical Parameters of Fungal Metabolites. IV. Moniliformin

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/57.6.1392 ◽

1974 ◽

Vol 57 (6) ◽

pp. 1392-1396 ◽

Cited By ~ 1

Author(s):

J A Lansden ◽

R J Clarkson ◽

W C Neely ◽

R J Cole ◽

J W Kirksey

Keyword(s):

Low Temperature ◽

Aqueous Solutions ◽

Ambient Temperature ◽

Emission Spectrum ◽

Potassium Salt ◽

Emission Spectra ◽

Fungal Metabolites ◽

Fungal Metabolite ◽

Fluorescence Excitation ◽

Phosphorescence Emission

Abstract The spectral data for a novel fungal metabolite, moniliformin (potassium salt of 1-hydroxycyclobut- 1-ene-3,4-dione), are reported. The corrected ambient temperature fluorescence excitation and emission spectra are given and the quantum efficiency is calculated to be 5.32 × 10舓3. The uncorrected low temperature phosphorescence emission spectrum and lifetime are also reported. Other physical data are given to support spectral evidence that the molecule exists as a dimer in aqueous solutions.

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Early Warning Detection of Carcinogens and Other Contaminants for Surface Water Treatment Plants using Simultaneous Absorbance-Transmittance and Fluorescence Excitation-Emission Spectroscopy

Biophysical Journal ◽

10.1016/j.bpj.2018.11.3053 ◽

2019 ◽

Vol 116 (3) ◽

pp. 568a

Author(s):

Adam M. Gilmore ◽

Linxi Chen

Keyword(s):

Water Treatment ◽

Surface Water ◽

Early Warning ◽

Emission Spectroscopy ◽

Fluorescence Excitation ◽

Surface Water Treatment ◽

Water Treatment Plants

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Fluorescence excitation and emission spectroscopy of the ÃA″1←X̃A′1 system of CHBr

The Journal of Chemical Physics ◽

10.1063/1.2183302 ◽

2006 ◽

Vol 124 (13) ◽

pp. 134302 ◽

Cited By ~ 26

Author(s):

Mihaela Deselnicu ◽

Chong Tao ◽

Calvin Mukarakate ◽

Scott A. Reid

Keyword(s):

Emission Spectroscopy ◽

Fluorescence Excitation

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The Position of Carotene in the D-1/D-2 Sub-Core Complex of Photosystem II

Zeitschrift für Naturforschung C ◽

10.1515/znc-1988-3-413 ◽

1988 ◽

Vol 43 (3-4) ◽

pp. 226-230 ◽

Cited By ~ 2

Author(s):

S. S. Brody

Keyword(s):

Low Temperature ◽

Photosystem Ii ◽

Fluorescence Spectrum ◽

Fluorescence Excitation Spectrum ◽

Core Complex ◽

Excitation Spectra ◽

Fluorescence Excitation ◽

Pheophytin A ◽

Long Wavelength ◽

Β Carotene

When the sub-core complex of photosystem II, D1/D2, is irradiated at 436 or 415 nm (absorption by chlorophyll and pheophytin and β-carotene) or 540 nm (absorption primarily by pheophytin), the low temperature fluorescence spectrum has two maxima, at 685 and 674 nm. This shows the existence of at least two different fluorescent forms of chlorophyll (chlorophyll a and perhaps pheophytin a). When carotene is irradiated at 485 nm (absorption primarily by β-carotene), only fluorescence at 685 nm is observed: this indicates that carotene is transferring energy to only the long-wavelength form of chlorophyll in the D1/D2 sub-core complex. The band of carotene (at 485 nm) does not appear in the fluorescence excitation spectrum, measured at 674 nm. The position of the carotene molecule relative to each of the fluorescent forms of chlorophyll was determined from the excitation spectra of each of the fluorescence bands.

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