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.

scholarly journals Branching ratios, radiative lifetimes, and transition dipole moments for tantalum nitride, TaN

2016 ◽  
Vol 325 ◽  
pp. 1-6 ◽  
Author(s):  
Jacob L. Bouchard ◽  
Timothy Steimle ◽  
Damian L. Kokkin ◽  
David J. Sharfi ◽  
Richard J. Mawhorter
Keyword(s):  
Dipole Moments ◽  
Branching Ratios ◽  
Tantalum Nitride ◽  
Transition Dipole ◽  
Radiative Lifetimes ◽  
Transition Dipole Moments

scholarly journals Branching Ratios, Radiative Lifetimes, and Transition Dipole Moments for YbOH

2020 ◽  
Vol 124 (16) ◽  
pp. 3135-3148 ◽  
Author(s):  
Ephriem Tadesse Mengesha ◽  
Anh T. Le ◽  
Timothy C. Steimle ◽  
Lan Cheng ◽  
Chaoqun Zhang ◽  
...  
Keyword(s):  
Dipole Moments ◽  
Branching Ratios ◽  
Transition Dipole ◽  
Radiative Lifetimes ◽  
Transition Dipole Moments

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

Modeling of Carbon Monoxide Two-Photon Laser-Induced Fluorescence (LIF) Spectra at High Temperature and Pressure

2020 ◽  
Vol 74 (6) ◽  
pp. 629-644
Author(s):  
Olivier Carrivain ◽  
Mikael Orain ◽  
Nelly Dorval ◽  
Céline Morin ◽  
Guillaume Legros
Keyword(s):  
Carbon Monoxide ◽  
Fluorescence Spectra ◽  
Laser Induced Fluorescence ◽  
Operating Conditions ◽  
Spectroscopic Constants ◽  
Fluorescence Signal ◽  
Excitation Spectra ◽  
Two Photon ◽  
Photon Excitation ◽  
Two Photon Excitation

In this study, quantitative model of two-photon excitation and fluorescence spectra of carbon monoxide based on up-to-date spectroscopic constants collected during an extensive literature survey was developed. This semi-classical model takes into account Hönl–London factors, quenching effects (collisional broadening and shift), ionization and stark effect (broadening and shift), whereas predissociation is neglected. It was specifically developed to first reproduce with a high confidence level the behavior of our experimental spectra obtained from laser-induced fluorescence (LIF) measurements, and then to allow us to extrapolate the fluorescence signal amplitude in other conditions than those used in these experiments. Synthetic two-photon excitation and fluorescence spectra of CO were calculated to predict the fluorescence signal at high pressures and temperatures, which are representative of gas turbine operating conditions. Comparison between experimental and calculated spectra is presented. Influence of temperature on both excitation and fluorescence spectra shapes and amplitudes is well reproduced by the simulated ones. It is then possible to estimate flame temperature from the comparison between experimental and calculated shapes of numerical excitation spectra. Influence of pressure on both excitation and fluorescence spectra was also investigated. Results show that for temperature below 600 K and pressure above 0.1 MPa, the usual Voigt profile is not suitable to reproduce the shape of the excitation spectrum. We found that the Lindholm profile is well suited to reproduce the pressure-dependence of the spectrum in the range 0.1 to 0.5 MPa at 300 K, and 0.1 to 0.7 MPa at 860 K. Beyond 0.7 MPa, in this temperature range, it is shown that the Lindholm profile does no longer match the spectral profiles, in particularly the red wing. Further analyses taking into account the line mixing phenomenon at higher pressure are thus discussed.

Vibrational branching ratios and radiative lifetimes in the laser cooling of AlBr

2017 ◽  
Vol 19 (7) ◽  
pp. 5519-5524 ◽  
Author(s):  
Yufeng Gao ◽  
Mingjie Wan
Keyword(s):  
Quantum Chemistry ◽  
Ab Initio ◽  
Laser Cooling ◽  
Branching Ratios ◽  
Radiative Lifetimes

The feasibility of laser cooling of the AlBr molecule is investigated usingab initioquantum chemistry.

Effects of UV-B Radiation on Laser-Induced Fluorescence Spectra in Crop Leaves

2001 ◽  
Vol 22 (2) ◽  
pp. 151-155 ◽  
Author(s):  
K. Mineuchi ◽  
K. Takahashi ◽  
H. Tatsumoto
Keyword(s):  
Fluorescence Spectra ◽  
Laser Induced Fluorescence
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