R2PI and MATI spectroscopy of 3-fluoro-5-methylanisole: Combined effect of meta-substituents on molecular conformation

Dai, Wenshuai; Zhang, Zhe; Du, Yikui

doi:10.1016/j.saa.2019.117398

Cited by 2 publications

(3 citation statements)

References 48 publications

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“…It is mainly caused by the rotation of the −CH 3 group, and such discontinuity does not affect the optimized results for both cis- and trans- rotamers at 0 and 180° in the D 0 state. Similar discontinuities were observed previously in the PECs of 2- N- methylaminopyridine . In this regard, the calculated IEs and relative stabilities of the two rotamers in the D 0 state are assumed to be not affected by the discontinuity at 90°.…”

Section: Resultssupporting

confidence: 71%

“…Similar discontinuities were observed previously in the PECs of 2-N-methylaminopyridine. 26 In this regard, the calculated IEs and relative stabilities of the two rotamers in the D 0 state are assumed to be not affected by the discontinuity at 90°.…”

Section: Resultsmentioning

confidence: 99%

“…For example, the cis- rotamer is observed to be stable for 3-fluoroanisole (3-F anisole) but not for 2-F anisole. , That is due to the fact that the steric effect between the F atom and the −OCH 3 group is weaker in 3-substituted ( meta -substituted) anisole than that in the 2-substituted one. The transition energies ( E 1 ) of Cl-substituted anisoles were found to be red-shifted compared to those of anisole, while those of F-substituted anisoles were found to be blue-shifted. ,− This is mainly caused by the different inductive effects of F and Cl atoms.…”

Section: Introductionmentioning

confidence: 93%

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Photoionization Spectroscopic and Theoretical Study on the Molecular Structures of cis- and trans-3-Chlorothioanisole

Zhang

Hou

et al. 2022

ACS Omega

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Resonance-enhanced two-photon ionization (R2PI) and massanalyzed threshold ionization (MATI) spectra are measured for the cis-and trans-3-chlorothioanisole (3ClTA). The first electronic excitation energy (E 1 ) and the adiabatic ionization energy (IE) of the cis-rotamer are determined to be 33 959±3 and 65 326±5 cm −1 , respectively, and those of the trans-rotamer are determined to be 34102±3 and 65 471±5 cm −1 , respectively. Density functional theory (DFT) calculations confirm that both the cis-and trans-rotamers of 3ClTA are stable and coexist in their respective S 0 , S 1 , and D 0 states. Both rotamers adopt planar structures with cis-being slightly more stable than trans-in the respective S 0 , S 1 , and D 0 states. The conformation, substitution, and isotope effects on the molecular structure, active vibrations, and electronic transition and ionization energies of 3ClTA are analyzed.

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Section: Resultssupporting

confidence: 71%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

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Photoionization Spectroscopic and Theoretical Study on the Molecular Structures of cis- and trans-3-Chlorothioanisole

Zhang

Hou

et al. 2022

ACS Omega

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Accurate determination of ionization energy of 1, 3-diethoxybenzene via photoionization efficiency spectrum in electrostatic field

Duan¹,

Li²,

Zhao³

et al. 2021

Acta Phys. Sin.

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Ionization energy (IE) is an important characteristic parameter of atoms or molecules. It plays an important role in the process of photophysics and photochemistry. The precise ionization energy is very important for relevant research. Especially, it is very useful for adjusting the signal of the zero-kinetic energy (ZEKE) spectrum, and it also plays a key role in judging the number of rotamers and molecular configuration. In linear time-of-flight mass spectrometers, pulsed electric fields are usually used to drive photo-ionized ions to the detector to produce the photoionization efficiency (PIE) spectrum. The ionization energy is directly obtained from the PIE curve. The uncertainty of the measured IE is usually greater than or equal to ± 10 cm–1. The ZEKE spectroscopy is based on the long-lived Rydberg state field ionization technology. In the ZEKE experiments, the laser excites molecules to the Rydberg state and then a pulsed field ionization (PFI) is used for measurement. A peak with high signal-to-noise ratio and narrow linewidth signal appears near the ionization threshold. Therefore, the more accurate ionization energy can be obtained, and the uncertainty of the measured value is about ± 5 cm–1. The 1,3-diethoxybenzene is an important benzene derivative, and experiments have confirmed that there are two rotamers, i.e. I (down-up) and III (down-down) in the supersonic molecular beam. In this paper, a linear time-of-flight mass spectrometer is used to measure the photoionization efficiency curves of 1,3-diethoxybenzene in electrostatic fields. From the linear fitting of the ionization energy values measured under different electric fields (Stark effect) to the square root of the field strengths, the precise ionization energy values of rotamer I and rotamer III are determined to be (62419 ± 2) cm–1 and (63378 ± 2) cm–1, respectively. Compared with the accuracies of the values measured by the usual pulsed electric field acceleration mechanism and the ZEKE spectroscopy, the accuracy is improved from about ± 10 and ± 5 to ± 2 cm–1, respectively. The physical mechanism, advantages and disadvantages of different methods are analyzed and discussed. The present research results show that the ionization energy measured in the electrostatic field is more accurate, the physical meaning of the measurement process is clear, and the threshold data are easy to collect. This is the first report on the precise ionization energy of 1,3-diethoxybenzene rotamers.

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R2PI and MATI spectroscopy of 3-fluoro-5-methylanisole: Combined effect of meta-substituents on molecular conformation

Cited by 2 publications

References 48 publications

Photoionization Spectroscopic and Theoretical Study on the Molecular Structures of cis- and trans-3-Chlorothioanisole

Photoionization Spectroscopic and Theoretical Study on the Molecular Structures of cis- and trans-3-Chlorothioanisole

Accurate determination of ionization energy of 1, 3-diethoxybenzene via photoionization efficiency spectrum in electrostatic field

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