Mass-analyzed threshold ionization spectroscopy of deuterium-substituted isotopomers of o-fluoroaniline and m-fluoroaniline cations

Yang, Shih Chang; Tzeng, Wen Bih

doi:10.1016/j.jms.2011.04.023

Cited by 3 publications

(4 citation statements)

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“…The expansion may result from the increased population of the antibonding orbital of the benzene ring. This is in agreement with the previous study that the S 1 ← S 0 transitions of benzene derivatives are mainly subjected to the π* ← π excitation of the benzene ring, as seen also from the plotted molecular orbitals involved in the excitation (Figure S4). For the F atom, the ∠C2C3F of different rotamers in the S 1 state is close to each other (117.4° for the planar cis- rotamer, 117.8° for the gauche- rotamer, and 117.3° for the trans- rotamer, Table ), indicating that the steric effect between the two substituents is not sensitive to the relative orientation of the −SCH 3 group in the S 1 state.…”

Section: Discussionsupporting

confidence: 93%

“…Previous studies showed that the activation extent of the substituent’s torsion mode in the low-frequency region of the 1C-R2PI spectrum is sensitive to the geometrical change upon photoexcitation. For example, the torsional band has been observed in the R2PI spectra of aniline − and NMA , derivatives, which are nonplanar in the S 0 state and become planar in the S 1 state; the torsion vibrational peak of trans- 2FTA has a slightly higher intensity than that of its 0 0 0 band in the R2PI spectrum . This is because trans -2FTA is planar in the S 0 state and becomes tilted with a C2–C1–S–C8 dihedral angle of ∼15° in the S 1 state .…”

Section: Discussionmentioning

confidence: 99%

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Substitution-induced Nonplanarity of 3-Fluorothioanisole in the First Electronically Excited State

Zhang

Hou

et al. 2022

J. Phys. Chem. A

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Vibronic spectra of 3-fluorothioanisole (3FTA) in the first electronic excited state (S1) and the cationic ground state (D0) have been obtained by one-color resonant two-photon ionization (1C-R2PI) and mass-analyzed threshold ionization (MATI) spectroscopy. Spectroscopic measurements and theoretical calculations indicate that both cis- and trans-rotamers of the 3FTA molecule are stable and coexist in the S0 (the electronic ground state) and D0 states, and the cis-rotamer is shown to be slightly more stable than the trans-rotamer. In the S1 state, theoretical calculations predict a stable gauche-structure of 3FTA, manifested by the observation of strong activation of the vibrational modes involving the motion of the −SCH3 group in the low-frequency regions of the 1C-R2PI and MATI spectra. The electronic excitation energy from the S0 state to the S1 state (E1) and the adiabatic ionization energy (IE) are respectively determined to be 34 820 ± 3 and 65 468 ± 5 cm–1 for cis-3FTA, and those of the trans-rotamer are respectively determined to be 35 047 ± 3 and 65 644 ± 5 cm–1. The structural properties of the stable rotamers of 3FTA and their comparison with other F- and Cl-substituted thioanisole derivatives are discussed as well.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Substitution-induced Nonplanarity of 3-Fluorothioanisole in the First Electronically Excited State

Zhang

Hou

et al. 2022

J. Phys. Chem. A

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“…And we try to attribute the most likely origins of these frequencies. First, we locate the signal of 105 cm −1 , which is compared with the MATI of the o -fluoroaniline [ 37 ]. The frequency observed is very close to the energy level difference (ΔE = 103 cm −1 ) between 0 0 and 10b 1 of the S l state origin.…”

Section: Resultsmentioning

confidence: 99%

“…We also see that all the photoelectron peaks almost reach the maximum or minimum at the same time, which means that the beat signals of the peaks are in the same direction basically. A careful review of the MATI of the o -fluoroaniline cation [ 37 ] shows that the intensity of the S l 0 0 state is maximal, and the vibrational peaks of the S l 10b 1 and S l 16a 1 states are almost invisible in the spectrum. Therefore, the transition probability of the S l 0 0 state is much higher than that of the S l 10b 1 and S l 16a 1 states in o -fluoroaniline ionization, or the FC factor of the S l 0 0 state is larger [ 15 ], making the S l 0 0 state easier to ionize, and the S l 10b 1 and S l 16a 1 states are much less likely to ionize.…”

Section: Resultsmentioning

confidence: 99%

Femtosecond Time-Resolved Observation of Relaxation and Wave Packet Dynamics of the S1 State in Electronically Excited o-Fluoroaniline

Abulimiti

et al. 2023

Molecules

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Quantum beat frequency is the basis for understanding interference effects and vibrational wave packet dynamics and has important applications. Using femtosecond time-resolved mass spectrometry and femtosecond time-resolved photoelectron image combined with theoretical calculations, we study the electronic excited-state relaxation of o-fluoroaniline molecule and the time-dependent evolution of vibrational wave packets between different eigenstates. After the molecule absorbs a photon of 288.3 nm and is excited to the S1 state, intramolecular vibrational redistribution first occurs on the time scale τ1 = 349 fs, and then the transition to the triplet state occurs through the intersystem crossing on the time scale τ2 = 583 ps, and finally, the triplet state occurs decays slowly through the time scale τ3 = 2074 ps. We find the intramolecular vibrational redistribution is caused by the 00, 10b1 and 16a1 vibrational modes of the Sl state origin. That is, the 288.3 nm femtosecond laser excites the molecule to the S1 state, and the continuous flow of the vibrational wave packet prepares a coherent superposition state of three vibrational modes. Through extracting the oscillation of different peak intensities in the photoelectron spectrum, we observe reversible changes caused by mutual interference of the S1 00, S1 10b1 and S1 16a1 states when the wave packets flow. When the pump pulse is 280 nm, the beat frequency disappears completely. This is explained in terms of increases in the vibrational field density and characteristic period of oscillation, and statistical averaging makes the quantum effect smooth and indistinguishable. In addition, the Rydberg component of the S1 state is more clearly resolved by combining experiment and theory.

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Mass-analyzed threshold ionization spectroscopy of 2,6-dimethylaniline, 2,6-dimethylaniline-NHD, and 2,6-dimethylaniline-ND2

Huang

Lin

Tzeng

2012

Chemical Physics Letters

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Mass-analyzed threshold ionization spectroscopy of deuterium-substituted isotopomers of o-fluoroaniline and m-fluoroaniline cations

Cited by 3 publications

References 32 publications

Substitution-induced Nonplanarity of 3-Fluorothioanisole in the First Electronically Excited State

Substitution-induced Nonplanarity of 3-Fluorothioanisole in the First Electronically Excited State

Femtosecond Time-Resolved Observation of Relaxation and Wave Packet Dynamics of the S1 State in Electronically Excited o-Fluoroaniline

Mass-analyzed threshold ionization spectroscopy of 2,6-dimethylaniline, 2,6-dimethylaniline-NHD, and 2,6-dimethylaniline-ND2

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