Insights into ultrafast decay dynamics of electronically excited pyridine-<i>N</i>-oxide

Feng, Baihui; Wu, Wenping; Yang, Shuaikang; He, Zhigang; Fang, Benjie; Yang, Dongyuan; Wu, Guorong; Yang, Xueming

doi:10.1039/d3cp06187f

Cited by 2 publications

(3 citation statements)

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“…In Figure b,c, it is worth mentioning that the contribution (the relative intensity) of τ 1 (50 fs) in the photoelectron transient is much smaller than that of τ 2 (680 fs) due to the different detection efficiency for a given fwhm value of the IRF and a given value of the time constant (τ i ), which can be mathematically described by the result of ⊗ IRF. A more detailed explanation about this in a similar situation has been given in our recent publication …”

Section: Resultsmentioning

confidence: 94%

“…A more detailed explanation about this in a similar situation has been given in our recent publication. 16 As mentioned above in Section 3.2, the component of τ 3 (τ 3 = ∞) will not be further discussed. For the time constant of τ 2 , it is straightforward to assign the derived value of 680 ± 20 fs to the lifetime of the highly excited vibrational states of the S 1 state.…”

Section: Trpes Spectrum At 2615 Nmmentioning

confidence: 99%

“…Small heterocyclic molecules are key building blocks of biomolecules in nature. For example, three kinds of the five natural DNA/RNA nucleobases, cytosine, thymine, and uracil, are pyrimidine-based organic molecules, the photochemistry of which has been widely studied over the past few decades. − The excited-state dynamics of prototypical heterocyclic molecules is potentially important for understanding the photoinduced biochemical processes in the earliest stages of prebiotic chemistry. , In recent years, we have investigated the ultrafast decay dynamics of a series of aromatic heterocyclic molecules containing the nitrogen (N) heteroatom, such as the substituted derivatives of pyrrole − and pyridine, − following excitations in the near-ultraviolet (UV) region of their respective electronic absorption spectra. The radiation-less relaxation dynamics of the low-lying electronic excited states of these isolated molecules and the substitution effects on the excited-state dynamics are better understood.…”

Section: Introductionmentioning

confidence: 99%

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Ultrafast Decay Dynamics of the 2¹ππ* Electronic State of N-Methyl-2-pyridone

Feng,

Wu,

et al. 2024

J. Phys. Chem. A

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The ultrafast decay dynamics of N-methyl-2-pyridone upon excitation in the near-ultraviolet range of 261.5−227.9 nm is investigated using the femtosecond timeresolved photoelectron spectroscopy method. Irradiation at 261.5 nm prepares N-methyl-2-pyridone molecules with high vibrational levels in the 1 1 ππ* state. The radiation-less decay to the ground state via internal conversion is suggested to be the dominant channel for the 1 1 ππ* state with large vibrational excess energy, which is revealed by a lifetime of 1.6 ± 0.2 ps. As the pump wavelength decreases, we found that irradiation at 238.5 and 227.9 nm results in the population of the 2 1 ππ* state. This is in agreement with the assignment of the vapor-phase UV absorption bands of N-methyl-2-pyridone. On the basis of the detailed analysis of our measured time-resolved photoelectron spectra at all pump wavelengths, we conclude that the 2 1 ππ* state has an ultrashort lifetime of 50 ± 10 fs. In addition, the S 1 (1 1 ππ*) state is subsequently populated via internal conversion and decays over a lifetime of 680−620 fs. The most probable whole deactivation pathway of the 2 1 ππ* state is discussed. This experimental study provides new insights into the excitation energy-dependent decay dynamics of electronically excited N-methyl-2-pyridone.

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Section: Resultsmentioning

confidence: 94%

Section: Trpes Spectrum At 2615 Nmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ultrafast Decay Dynamics of the 2¹ππ* Electronic State of N-Methyl-2-pyridone

Feng,

Wu,

et al. 2024

J. Phys. Chem. A

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Insights into Ultrafast Relaxation Dynamics of Electronically Excited Furfural and 5-Methylfurfural

Wu,

Feng,

Tian

et al. 2024

J. Phys. Chem. A

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The ultrafast relaxation dynamics of furfural and 5methylfurfural following excitation in the ultraviolet range is investigated using the femtosecond time-resolved photoelectron spectroscopy method. Specifically, the pump wavelength-dependent decay dynamics of electronically excited furfural and 5-methylfurfural is discussed on the basis of a detailed analysis of our measured time-resolved photoelectron spectroscopy spectra. Irradiation at all pump wavelengths prepares both furfural and 5methylfurfural molecules with different vibrational levels in the first optically bright S 2 ( 1 ππ*) state, the lifetime of which is measured to be at least hundreds of femtoseconds. Besides the prominent deactivation channels of ring-opening and ring-puckering pathways for the S 2 ( 1 ππ*) state, we propose that there is a minor decay channel of internal conversion from the initially prepared S 2 ( 1 ππ*) state to the S 1 ( 1 nπ*) state. The wavepacket decays out of the Franck−Condon region on the S 2 ( 1 ππ*) state potential energy surface and bifurcates into different parts somewhere. A small fraction of the wavepacket funnels down to the S 1 ( 1 nπ*) state via internal conversion. The subsequently populated S 1 ( 1 nπ*) state contains large vibrational excess energy and decays over a lifetime of 2.5−2.8 ps. One of the deactivation channels of the S 1 ( 1 nπ*) state is intersystem crossing to the 3 ππ* triplet state. In addition, methyl substitution effects on the excitedstate dynamics of furfural are also discussed. This experimental study provides new insights into the excitation energy-dependent decay dynamics of photoexcited furfural and 5-methylfurfural.

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Insights into ultrafast decay dynamics of electronically excited pyridine-N-oxide

Abstract: The ultrafast decay dynamics of pyridine-N-oxide upon excitation in the near-ultraviolet range of 340.2-217.6 nm is investigated using femtosecond time-resolved photoelectron imaging technique. The time-resolved photoelectron spectra and photoelectron angular...

Cited by 2 publications

References 51 publications

Ultrafast Decay Dynamics of the 2¹ππ* Electronic State of N-Methyl-2-pyridone

Ultrafast Decay Dynamics of the 2¹ππ* Electronic State of N-Methyl-2-pyridone

Insights into Ultrafast Relaxation Dynamics of Electronically Excited Furfural and 5-Methylfurfural

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Insights into ultrafast decay dynamics of electronically excited pyridine-N-oxide

Abstract: The ultrafast decay dynamics of pyridine-N-oxide upon excitation in the near-ultraviolet range of 340.2-217.6 nm is investigated using femtosecond time-resolved photoelectron imaging technique. The time-resolved photoelectron spectra and photoelectron angular...

Cited by 2 publications

References 51 publications

Ultrafast Decay Dynamics of the 21ππ* Electronic State of N-Methyl-2-pyridone

Ultrafast Decay Dynamics of the 21ππ* Electronic State of N-Methyl-2-pyridone

Insights into Ultrafast Relaxation Dynamics of Electronically Excited Furfural and 5-Methylfurfural

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Ultrafast Decay Dynamics of the 2¹ππ* Electronic State of N-Methyl-2-pyridone

Ultrafast Decay Dynamics of the 2¹ππ* Electronic State of N-Methyl-2-pyridone