Laser induced fluorescence study of the - transition of FCH2CH2O

Chhantyal-Pun, Rabi; Chen, Ming-Wei; Miller, Terry A.

doi:10.1016/j.cplett.2012.11.009

Cited by 5 publications

(10 citation statements)

References 43 publications

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“…The survey scan showing the vibronic structure of the B ̃← X ̃excitation transition of MFEO is illustrated in Figure 2. The spectrum is very similar to the LIF spectrum of MFEO published by Chhantyal-Pun et al; 34 the band positions do not differ in the two spectra by more than 2−3 cm −1 . The difference is a bit larger when the relative band intensities are compared.…”

Section: ■ Introductionsupporting

confidence: 86%

“…In contrast to this, due to the strong C–F bond, fluorinated alkoxy radicals are the major products of the photochemical decompositions of fluorinated alkyl nitrites. Among the fluorinated alkoxy radicals, trifluoromethoxy (CF 3 O) and β-monofluoroethoxy (CH 2 F–CH 2 O), and the unsaturated 1-fluorovinoxy (CH 2 CFO) − and cis - and trans -1,2-difluorovinoxy radicals (CFHCFO) were studied by LIF spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

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Revealing Long-Range Substituent Effects in the Laser-Induced Fluorescence and Dispersed Fluorescence Spectra of Jet-Cooled CH_xF_3–xCH₂O (x = 1, 2, 3) Radicals

et al. 2019

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The B ̃−X ̃laser-induced fluorescence (LIF) and dispersed fluorescence (DF) spectra of the atmospherically important β-monofluoro ethoxy (MFEO), β,β-difluoro ethoxy (DFEO), and β,β,β-trifluoro ethoxy (TFEO) radicals were recorded with vibronic resolution under jet-cooled conditions. To simulate the spectra, Franck−Condon factors were obtained from quantum chemical computations carried out at the CAM-B3LYP/6-311++G(d,p) level of theory. The simulations reproduce well both the LIF and DF spectra. Both conformers (G and T) of MFEO and one (G) of the two conformers of DFEO contribute to the LIF spectrum. A comparison between the experimental and calculated spectra confirms the expected longrange field effects of the CH x F 3−x group on electronic transition energies and bond strengths, especially in the excited electronic (B ̃) state. Although TFEO has only one conformer, its LIF spectrum is highly congested, which is attributed to the interaction between CO stretch and the −CF 3 internal rotation.

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Section: ■ Introductionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Revealing Long-Range Substituent Effects in the Laser-Induced Fluorescence and Dispersed Fluorescence Spectra of Jet-Cooled CH_xF_3–xCH₂O (x = 1, 2, 3) Radicals

et al. 2019

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“…21 The simulation assumes equal dipole components in the two orthogonal directions perpendicular to the CO bond and zero along the bond, which is the situation with methoxy. This assumption yields equal transition moments in the bc symmetry plane and perpendicular to it.…”

Section: E Fitting the High-resolution Lif Spectrummentioning

confidence: 99%

“…In particular, T 00 was determined to be 68(10) cm −1 for isopropoxy 7 and a more recent determination 21 with higher precision places it at 60.8(1.0) cm −1 . Some time ago, the origin band of thẽ B −X LIF transition of isopropoxy was recorded with a partially resolved rotational contour (K-manifolds unresolved).…”

Section: Introductionmentioning

confidence: 95%

Rotationally resolved ${\tilde{B}} \leftarrow {\tilde{X}}$B̃←X̃ electronic spectra of the isopropoxy radical: A comparative study

Liu

Melnik

Miller

2013

The Journal of Chemical Physics

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112

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The B̃-X̃ laser-induced-fluorescence spectrum of jet-cooled isopropoxy radical (i-C3H7O[middle dot]) has been recorded. Using an isolated state model the observed rotational and fine structure of the origin band has been well simulated to determine rotational constants for both the X̃ and B̃ states and the electron spin-rotation constants of the X̃ state. The line intensities are well simulated with a parallel transition type, requiring the same symmetry for the levels involved of each the X̃ and B̃ state, which confirms the previous suggestion that going from ethoxy (C2H5O[middle dot]) to isopropoxy, the energy ordering of the electron configurations with in- and out-of-plane half-filled p-orbitals of the oxygen atom is reversed and the ground vibronic symmetry changes from a" to a'. However, the observed spin-rotation coupling constants are not consistent with their predication from either semi-empirical theory or quantum chemical calculations. Additionally, the lack of observed transitions involving the out-of-plane transition moment component is not consistent with high level electronic structure calculations suggesting mixing of vibronic levels by strong spin-orbit coupling. A new twofold model has been developed that explicitly includes Coriolis and spin-orbit coupling between different vibronic levels. This model renders the discrepancy between theoretical and experimental spin-rotation constants moot. Moreover, it determines independently the contributions to the observed splitting between the lowest two levels, resulting from non-relativistic kinetic and Coulombic effects, and that due to the relativistic spin-orbit interaction. The experimental values show that these effects are comparable, but that the vibronic one is slightly more important. This result is at variance with state-of-the-art electronic structure calculations which otherwise do a remarkably good job of describing the ground state of isopropoxy.

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“…It is well-known that formaldehyde can be generated via β C−C bond fission of highly excited alkoxy radicals produced with 355 nm laser photolysis under jet-cooled conditions. 131 Comparing between the two free radicals investigated in the present work, DF spectra of both conformers of isobutoxy contain sharp lines, while transitions in the DF spectra of 2-methyl-1-butoxy are broadened. Similarly, lines in the previously reported DF spectra of 2-butoxy were significantly broader than 1-butoxy, 34 which was attributed to the smaller Ã−X̃ separation of 2-butoxy when compared to 1-butoxy, and hence stronger vibronic interaction between the Ãand X-states.…”

Section: Discussionmentioning

confidence: 61%

Laster spectroscopic investigations of organic alkoxy and peroxy radicals.

Reza¹

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like to thank the department for having faith in me and admitting me into the Ph.D. program. First, I would like to express my gratitude to my advisor, Jinjun Liu, for his constant guidance and support and for giving me training in science beyond my imagination. His time and patience were really helpful in achieving my goals. I need to also acknowledge my dissertation defense committee members, Dr. Richard J. Wittebort, Dr. Lee Thompson, and Dr. Sergio B. Mendes. Thanks for being there in the key moment of my graduate school career. Next, I have to thank Neil J. Reilly to whom I owe a lot of what I know about the laser-induced fluorescence and dispersed fluorescence system. It was a wonderful experience to work with all the other members of the Liu group, specially Opu, and Hamzeh. I also want to acknowledge the incredible support from the staff, especially Steve, Sherry, Carla, Ben, Jason, and Renu, in the Department of Chemistry. Your kindness and care towards me have been very welcoming during my time here at UofL. v I thank my parents, who always encouraged me and took great pride in my progress in this endeavor. Outside of my lab, I am very much indebted to my dearest friend Dhruba Kumar Pattadar for his timely help and invaluable suggestions during my Ph.D. course work. I am also grateful to my brother and their families for their support and advice in every possible way. My in-laws have stood by me always. I thank them for their encouragement. Finally, I would like to thank my beloved wife, Rumpa, for being with me and her encouragement and support to pursue my Ph.D. degree.

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Laser induced fluorescence study of the - transition of FCH2CH2O

Cited by 5 publications

References 43 publications

Revealing Long-Range Substituent Effects in the Laser-Induced Fluorescence and Dispersed Fluorescence Spectra of Jet-Cooled CH_xF_3–xCH₂O (x = 1, 2, 3) Radicals

Revealing Long-Range Substituent Effects in the Laser-Induced Fluorescence and Dispersed Fluorescence Spectra of Jet-Cooled CH_xF_3–xCH₂O (x = 1, 2, 3) Radicals

Rotationally resolved ${\tilde{B}} \leftarrow {\tilde{X}}$B̃←X̃ electronic spectra of the isopropoxy radical: A comparative study

Laster spectroscopic investigations of organic alkoxy and peroxy radicals.

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Laser induced fluorescence study of the - transition of FCH2CH2O

Cited by 5 publications

References 43 publications

Revealing Long-Range Substituent Effects in the Laser-Induced Fluorescence and Dispersed Fluorescence Spectra of Jet-Cooled CHxF3–xCH2O (x = 1, 2, 3) Radicals

Revealing Long-Range Substituent Effects in the Laser-Induced Fluorescence and Dispersed Fluorescence Spectra of Jet-Cooled CHxF3–xCH2O (x = 1, 2, 3) Radicals

Rotationally resolved ${\tilde{B}} \leftarrow {\tilde{X}}$B̃←X̃ electronic spectra of the isopropoxy radical: A comparative study

Laster spectroscopic investigations of organic alkoxy and peroxy radicals.

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Revealing Long-Range Substituent Effects in the Laser-Induced Fluorescence and Dispersed Fluorescence Spectra of Jet-Cooled CH_xF_3–xCH₂O (x = 1, 2, 3) Radicals

Revealing Long-Range Substituent Effects in the Laser-Induced Fluorescence and Dispersed Fluorescence Spectra of Jet-Cooled CH_xF_3–xCH₂O (x = 1, 2, 3) Radicals