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

Feng，Baihui1,2; Wu，Wenping1,2; He，Zhigang1; Yang，Dongyuan1; Wu，Guorong1; Yang，Xueming1,3

2024-05-16

10.1021/acs.jpca.4c01418

Journal of Physical Chemistry A   影响因子和分区

1089-5639

1520-5215

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 time-resolved photoelectron spectroscopy method. Irradiation at 261.5 nm prepares N-methyl-2-pyridone molecules with high vibrational levels in the 1ππ* state. The radiation-less decay to the ground state via internal conversion is suggested to be the dominant channel for the 1ππ* 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 2ππ* 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 2ππ* state has an ultrashort lifetime of 50 ± 10 fs. In addition, the S(1ππ*) state is subsequently populated via internal conversion and decays over a lifetime of 680-620 fs. The most probable whole deactivation pathway of the 2ππ* state is discussed. This experimental study provides new insights into the excitation energy-dependent decay dynamics of electronically excited N-methyl-2-pyridone.

SCI ; EI

英语

其他

CHEMISTRY

2-s2.0-85192223104

Scopus

1.State Key Laboratory of Molecular Reaction Dynamics,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian,457 Zhongshan Road, Liaoning,116023,China
2.University of Chinese Academy of Sciences,Beijing,100049,China
3.Department of Chemistry,College of Science,Southern University of Science and Technology,Shenzhen,518055,China

Feng，Baihui,Wu，Wenping,He，Zhigang,et al. Ultrafast Decay Dynamics of the 21ππ* Electronic State of N-Methyl-2-pyridone[J]. Journal of Physical Chemistry A,2024,128(19):3840-3847.

Feng，Baihui,Wu，Wenping,He，Zhigang,Yang，Dongyuan,Wu，Guorong,&Yang，Xueming.(2024).Ultrafast Decay Dynamics of the 21ππ* Electronic State of N-Methyl-2-pyridone.Journal of Physical Chemistry A,128(19),3840-3847.

Feng，Baihui,et al."Ultrafast Decay Dynamics of the 21ππ* Electronic State of N-Methyl-2-pyridone".Journal of Physical Chemistry A 128.19(2024):3840-3847.