Laser-induced fluorescence and discharge emission spectra of CrO. Rotational analysis of the A5Π–X5Π transition

1980 ◽  
Vol 58 (4) ◽  
pp. 516-533 ◽  
Author(s):  
W. H. Hocking ◽  
A. J. Merer ◽  
D. J. Milton ◽  
W. E. Jones ◽  
G. Krishnamurty
Keyword(s):  
Fluorescence Spectra ◽  
Rotational Temperature ◽  
Electronic States ◽  
Emission Spectra ◽  
Laser Induced Fluorescence ◽  
Spin Orbit Coupling ◽  
Excitation Spectra ◽  
Large Numbers ◽  
Parallel Polarization ◽  
Indirect Information

The A5Π–X5Π electronic transition of CrO, near 6000 Å, has been analysed in detail using laser-induced fluorescence and conventional discharge emission spectroscopy. The transition provides the first instance where it has been possible to analyse the rotational structures of quintet electronic states completely. Although the parallel polarization of the transition has prevented the spin–orbit coupling and Λ-doubling intervals from being observed directly, it is shown that sufficient indirect information exists in the spectrum for them to be obtained with fair precision. The excited state, A5Π, is perturbed by large numbers of other electronic states which have no intensity of their own for emission to the ground state. The analysis of the perturbed regions has been greatly facilitated by the laser-induced fluorescence spectra: the excitation spectra correspond to a rotational temperature close to room temperature (which offers a significant improvement in resolution over the discharge spectra), and the J-assignments of the perturbed lines given by the resolved fluorescence spectra are unambigious

General discussion: electronic emission spectroscopy of CF+4 and SiF+4

1988 ◽  
Vol 324 (1578) ◽  
pp. 289-293 ◽  
Keyword(s):  
Emission Spectroscopy ◽  
Molecular Beam ◽  
Rotational Temperature ◽  
Electronic States ◽  
Emission Spectra ◽  
Fluorescence Decay ◽  
Molecular Ions ◽  
Dissociation Channel ◽  
Excited Electronic States ◽  
Beam Electron

We report the observation of electronic emission spectra in the tetrahedral molecular ions CF+4 and SiF+4. The spectra are observed at a low rotational temperature (less than 30 K) in a crossed molecular-beam - electron-beam apparatus (Carrington & Tuckett 1980). These spectra are especially interesting because the fluorescing states in the two ions lie up to 10 eV above their lowest dissociation channel (to CF+3/SiF+3 + F; see figure 1), and these states might be expected to decay non-radiatively rather than by a radiative channel. The observation of fluorescence decay from highly excited electronic states of these polyatomic ions is therefore a very surprising phenomenon.

Laser-induced fluorescence excitation spectroscopy of N2 + produced by VUV photoionization of N2 and N2O

1998 ◽  
Vol 5 (3) ◽  
pp. 1069-1071 ◽  
Author(s):  
Masakazu Mizutani ◽  
Hiromichi Niikura ◽  
Atsunari Hiraya ◽  
Koichiro Mitsuke
Keyword(s):  
Second Harmonic ◽  
Rotational Temperature ◽  
Wavelength Region ◽  
Grazing Incidence ◽  
Spectral Width ◽  
Laser Induced Fluorescence ◽  
Laser Wavelength ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Vuv Photoionization

Synchrotron radiation emitted from the UVSOR storage ring is monochromated by a grazing-incidence monochromator and introduced coaxially with the second harmonic of a mode-locked Ti:sapphire laser. Sample gases, N2 and N2O, are photoionized into vibronically ground N2 + with the fundamental light of the undulator radiation at 18.0 and 18.6 eV, respectively. Laser-induced fluorescence (LIF) excitation spectra of N2 + from N2 and N2O are measured in the laser wavelength region of the (B 2Σ u +, v′ = 0) ← (X 2Σg +, v′′ = 0) transition at 389–392 nm. The LIF excitation spectra of N2 + exhibit two maxima due to the P and R branches in which rotational bands are heavily overlapped. The rotational temperature is determined by simulating an LIF excitation spectrum by using the theoretical intensity distribution of rotation bands convoluted with the spectral width of the laser.

Fourier Transform Fluorescence Spectrometry

1988 ◽  
Vol 42 (8) ◽  
pp. 1563-1566 ◽  
Author(s):  
B. Hlivko ◽  
H. Hong ◽  
R. R. Williams
Keyword(s):  
Fourier Transform ◽  
Fluorescence Polarization ◽  
Fluorescence Spectra ◽  
Laser Excitation ◽  
Emission Spectra ◽  
Laser Fluorescence ◽  
Fluorescence Spectrometry ◽  
Excitation Spectra ◽  
Polarization Spectra ◽  
Monochromatic Source

A variety of fluorescence spectra have been measured interferometrically, demonstrating the feasibility of Fourier Transform Fluorescence Spectrometry (FT-FS). Emission spectra have been measured with the use of a monochromatic source and an interferometer as the emission selector. Excitation spectra have been measured with the use of a multi-line laser. Fluorescence polarization spectra have also been recorded with the use of laser excitation. The analytical characteristics of working curves are discussed.

scholarly journals Assisted Interpretation of Laser-Induced Fluorescence Spectra of Egg-Based Binding Media Using Total Emission Fluorescence Spectroscopy

2006 ◽  
Vol 2006 ◽  
pp. 1-5 ◽  
Author(s):  
Austin Nevin ◽  
Demetrios Anglos
Keyword(s):  
Amino Acids ◽  
Fluorescence Spectroscopy ◽  
Fluorescence Spectra ◽  
Emission Spectra ◽  
Egg Yolk ◽  
Laser Induced Fluorescence ◽  
Oxidation Products ◽  
Total Emission ◽  
Binding Media ◽  
Age Related

Laser-induced fluorescence (LIF) spectroscopy can provide nondestructive, qualitative analysis of protein-based binding media found in artworks. Fluorescence emissions from proteins in egg yolk and egg white are due to autofluorescent aromatic amino acids as well as other native and age-related fluorophores, but the potential of fluorescence spectroscopy for the differentiation between binding media is dependent on the choice of a suitable excitation wavelength and limited by problems in interpretation. However, a better understanding of emission spectra associated with LIF can be achieved following comparisons with total emission fluorescence spectra where a series of consecutive emission spectra are recorded over a specific range. Results using nanosecond UV laser sources for LIF of egg-based binding media are presented which are rationalised following comparisons with total emission spectra. Specifically, fluorescence is assigned to tryptophan and oxidation products of amino acids; in the case of egg yolk, fatty-acid polymerisation and age-related degradation products account for the formation of fluorophores.

Correction of Fluorescence Spectra

1994 ◽  
Vol 48 (4) ◽  
pp. 436-447 ◽  
Author(s):  
J. W. Hofstraat ◽  
M. J. Latuhihin
Keyword(s):  
Absorption Spectra ◽  
Wavelength Range ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Wavelength Dependence ◽  
Excitation Spectra ◽  
Excitation Light ◽  
Radiative Processes ◽  
Sensing Applications

Several methods that can be applied to remove wavelength-dependent instrumental effects from fluorescence emission and excitation spectra have been investigated. Removal of such artifacts is necessary for the comparison of spectra that have been obtained on different instruments. Without correction, spectral line positions and relative intensities will be instrument-determined to a great extent. Furthermore, the application of adequate correction procedures provides excitation spectra which can be directly compared to absorption spectra; comparison of corrected excitation spectra and absorption spectra can be used to interpret the efficiency and pathways of radiative processes. Finally, corrected reflection spectra can be obtained, which can be directly transformed into absorption spectra and are useful for remote sensing applications. The methods that have been studied for the correction of emission spectra are the application of a standard lamp with calibrated spectral output and the use of fluorescence standards. The standards are a series of luminescent phosphors in polymer films and a solution of quinine sulfate dihydrate in perchloric acid, all provided with certified spectral emission values. For correction of excitation spectra, a quantum counter was applied. Several quantum counters were investigated. The best results were obtained for application of a mixture of the dyes basic blue and HITC, which provided good correction for the wavelength range 250 to 820 nm. No good quantum counters have been reported thus far for this (large) wavelength range. Correction for wavelength dependence of the excitation optics was realized by measurement of the excitation light intensity at the sample position and at the reference position with a Si photodiode. Correction factors for the excitation spectra were checked with a number of reference materials. Attention has also been paid to polarization-dependent effects that may occur in fluorescence spectra. The application of correction procedures was demonstrated for phytoplankton fluorescence spectra.

Theoretical Study on Fluorescence Spectra of Three Coumarin Derivatives

2013 ◽  
Vol 389 ◽  
pp. 25-28 ◽  
Author(s):  
Ying Wang
Keyword(s):  
Fluorescence Spectra ◽  
Vibrational Analysis ◽  
Emission Spectra ◽  
Dft Method ◽  
Excited Configuration ◽  
Coumarin Derivatives ◽  
Excitation Spectra ◽  
Geometric Configurations ◽  
Td Dft ◽  
Experimental Values

The fluorescence spectra of three coumarin derivatives are studied. Geometric configurations of the three compounds are optimized by DFT method of quantum chemistry on B3LYP/6-31G. There is no imaginary frequency in vibrational analysis. Their excitation spectra are calculated by TD-DFT method. Furthermore, geometric configurations in excited state of the three compounds are optimized by CIS method. Based on the excited configuration emission spectra are also calculated. All the calculated results are in good agreement with experimental values.

Laser-induced fluorescence experimental spectroscopy and theoretical calculations of uranium monoxide

2021 ◽  
Author(s):  
Xi-Lin Bai ◽  
Xue-Dong Zhang ◽  
Fu-Qiang Zhang ◽  
Timothy C. Steimle
Keyword(s):  
Chemical Bonding ◽  
Fluorescence Spectra ◽  
Theoretical Calculations ◽  
Branching Ratios ◽  
Laser Induced Fluorescence ◽  
Theory Model ◽  
Ligand Field ◽  
Excitation Spectra ◽  
Transition Dipole ◽  
Radiative Lifetimes

Abstract As a model molecule of actinide chemistry, UO molecule plays an important role in understanding the electronic structure and chemical bonding of actinide-containing species. We report a study of the laser-induced fluorescence spectra of the U16O and U18O using two-dimensional spectroscopy. Several rotationally resolved excitation spectra were investigated. Accurate molecular rotational constants and equilibrium internuclear distances were reported. Low-lying electronic states information was extracted from high resolution dispersed fluorescence spectra and analyzed by the ligand field theory model. The configuration of the ground state was determined as U2+(5f37s)O2-. The branching ratios, and the vibrational harmonic and anharmonic parameters were also obtained. Radiative lifetimes were determined by recording the time-resolved fluorescence spectroscopy. Transition dipole moments were calculated using the branching ratios and the radiative lifetimes. These findings were elucidated by using quantum-chemical calculations, and the chemical bonding was also analyzed. The findings presented in this work will enrich our understanding of actinide-containing molecules.

Factors influencing fluorescence spectra of free porphyrins.

1988 ◽  
Vol 34 (4) ◽  
pp. 757-760 ◽  
Author(s):  
C F Polo ◽  
A L Frisardi ◽  
E R Resnik ◽  
A E Schoua ◽  
A M Batlle
Keyword(s):  
Ionic Strength ◽  
Fluorescence Spectra ◽  
Emission Spectra ◽  
Main Peak ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Experimental Conditions ◽  
Organic Mixture ◽  
Carbonate Buffer ◽  
Factors Influencing

Abstract We recorded fluorescence excitation and emission spectra of uro- and coproporphyrin under different experimental conditions, to see how these conditions influence quantifications based on measurement of fluorescence intensity. We found that, for bands alpha and beta of the emission spectra and the main peak of the excitation spectra, fluorescence depends on pH and is minimal near pH 5 and near pH 7-7.5 for copro- and uroporphyrin, respectively. For band gamma of the emission spectra there was a constant decrease of fluorescence with increasing alkalinity of the solution. The intensity of porphyrin fluorescence also depends on ionic strength, reaching sharp maxima at 0.1 mol/L (for uroporphyrin) and 1 mol/L (for coproporphyrin). The organic mixture ethyl acetate:acetic acid (4:1 by vol), commonly used to extract porphyrins from biological samples, markedly diminishes the fluorescence of both porphyrins as compared with the same concentration of each porphyrin in aqueous acidic solvent. Furthermore, when we measured different ratios of uro:copro mixture at three distinct pHs and buffers, we found that at pH 10.5 (in carbonate buffer) the measured units of fluorescence depend only on total porphyrin concentration and not on the composition of the mixture.

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