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Title: Excited state non-adiabatic dynamics of N-methylpyrrole: A time-resolved photoelectron spectroscopy and quantum dynamics study

The dynamics of N-methylpyrrole following excitation at wavelengths in the range 241.5-217.0 nm were studied using a combination of time-resolved photoelectron spectroscopy (TRPES), ab initio quantum dynamics calculations using the multi-layer multi-configurational time-dependent Hartree method, as well as high-level photoionization cross section calculations. Excitation at 241.5 and 236.2 nm results in population of the A{sub 2}(πσ{sup ∗}) state, in agreement with previous studies. Excitation at 217.0 nm prepares the previously neglected B{sub 1}(π3p{sub y}) Rydberg state, followed by prompt internal conversion to the A{sub 2}(πσ{sup ∗}) state. In contrast with the photoinduced dynamics of pyrrole, the lifetime of the wavepacket in the A{sub 2}(πσ{sup ∗}) state was found to vary with excitation wavelength, decreasing by one order of magnitude upon tuning from 241.5 nm to 236.2 nm and by more than three orders of magnitude when excited at 217.0 nm. The order of magnitude difference in lifetimes measured at the longer excitation wavelengths is attributed to vibrational excitation in the A{sub 2}(πσ{sup ∗}) state, facilitating wavepacket motion around the potential barrier in the N–CH{sub 3} dissociation coordinate.
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [1] ;  [4] ;  [5] ;  [6] ;  [7] ;  [1] ;  [8] ;  [8]
  1. National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6 (Canada)
  2. (China)
  3. Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5 (Canada)
  4. (Sweden)
  5. Department of Applied Physics, Hokkaido University, Kita-13 Nishi-8, Kita-ku, Sapporo 060-8628 (Japan)
  6. School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom)
  7. School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)
  8. (Canada)
Publication Date:
OSTI Identifier:
22493619
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 144; Journal Issue: 1; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; COORDINATES; CROSS SECTIONS; DISSOCIATION; EXCITATION; INTERNAL CONVERSION; LAYERS; LIFETIME; PHOTOELECTRON SPECTROSCOPY; PHOTOIONIZATION; POTENTIALS; PYRROLES; RYDBERG STATES; TIME DEPENDENCE; TIME RESOLUTION; WAVE PACKETS; WAVELENGTHS