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Title: Ultraviolet photolysis of adenine: Dissociation via the {sup 1}{pi}{sigma}{sup *} state

Abstract

High resolution total kinetic energy release (TKER) spectra of the H atom fragments resulting from photodissociation of jet-cooled adenine molecules at 17 wavelengths in the range 280>{lambda}{sub phot}>214 nm are reported. TKER spectra obtained at {lambda}{sub phot}>233 nm display broad, isotropic profiles that peak at low TKER ({approx}1800 cm{sup -1}) and are largely insensitive to the choice of excitation wavelength. The bulk of these products is attributed to unintended multiphoton dissociation processes. TKER spectra recorded at {lambda}{sub phot}{<=}233 nm display additional fast structure, which is attributed to N{sub 9}-H bond fission on the {sup 1}{pi}{sigma}{sup *} potential energy surface (PES). Analysis of the kinetic energies and recoil anisotropies of the H atoms responsible for the fast structure suggests excitation to two {sup 1}{pi}{pi}{sup *} excited states (the {sup 1}L{sub a} and {sup 1}B{sub b} states) at {lambda}{sub phot}{approx}230 nm, both of which dissociate to yield H atoms together with ground state adeninyl fragments by radiationless transfer through conical intersections with the {sup 1}{pi}{sigma}{sup *} PES. Parallels with the photochemistry exhibited by other, smaller heteroaromatics (pyrrole, imidazole, phenol, etc.) are highlighted, as are inconsistencies between the present conclusions and those reached in two other recent studies of excited state adenine molecules.

Authors:
; ; ;  [1]
  1. School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom)
Publication Date:
OSTI Identifier:
20991231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 126; Journal Issue: 12; Other Information: DOI: 10.1063/1.2712843; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ADENINES; DISSOCIATION; EXCITATION; EXCITED STATES; GROUND STATES; IMIDAZOLES; KINETIC ENERGY; MULTI-PHOTON PROCESSES; PHENOL; PHOTOCHEMISTRY; PHOTOLYSIS; PHOTON-MOLECULE COLLISIONS; PYRROLES; ULTRAVIOLET RADIATION

Citation Formats

Nix, Michael G. D., Devine, Adam L., Cronin, Brid, and Ashfold, Michael N. R. Ultraviolet photolysis of adenine: Dissociation via the {sup 1}{pi}{sigma}{sup *} state. United States: N. p., 2007. Web. doi:10.1063/1.2712843.
Nix, Michael G. D., Devine, Adam L., Cronin, Brid, & Ashfold, Michael N. R. Ultraviolet photolysis of adenine: Dissociation via the {sup 1}{pi}{sigma}{sup *} state. United States. doi:10.1063/1.2712843.
Nix, Michael G. D., Devine, Adam L., Cronin, Brid, and Ashfold, Michael N. R. Wed . "Ultraviolet photolysis of adenine: Dissociation via the {sup 1}{pi}{sigma}{sup *} state". United States. doi:10.1063/1.2712843.
@article{osti_20991231,
title = {Ultraviolet photolysis of adenine: Dissociation via the {sup 1}{pi}{sigma}{sup *} state},
author = {Nix, Michael G. D. and Devine, Adam L. and Cronin, Brid and Ashfold, Michael N. R.},
abstractNote = {High resolution total kinetic energy release (TKER) spectra of the H atom fragments resulting from photodissociation of jet-cooled adenine molecules at 17 wavelengths in the range 280>{lambda}{sub phot}>214 nm are reported. TKER spectra obtained at {lambda}{sub phot}>233 nm display broad, isotropic profiles that peak at low TKER ({approx}1800 cm{sup -1}) and are largely insensitive to the choice of excitation wavelength. The bulk of these products is attributed to unintended multiphoton dissociation processes. TKER spectra recorded at {lambda}{sub phot}{<=}233 nm display additional fast structure, which is attributed to N{sub 9}-H bond fission on the {sup 1}{pi}{sigma}{sup *} potential energy surface (PES). Analysis of the kinetic energies and recoil anisotropies of the H atoms responsible for the fast structure suggests excitation to two {sup 1}{pi}{pi}{sup *} excited states (the {sup 1}L{sub a} and {sup 1}B{sub b} states) at {lambda}{sub phot}{approx}230 nm, both of which dissociate to yield H atoms together with ground state adeninyl fragments by radiationless transfer through conical intersections with the {sup 1}{pi}{sigma}{sup *} PES. Parallels with the photochemistry exhibited by other, smaller heteroaromatics (pyrrole, imidazole, phenol, etc.) are highlighted, as are inconsistencies between the present conclusions and those reached in two other recent studies of excited state adenine molecules.},
doi = {10.1063/1.2712843},
journal = {Journal of Chemical Physics},
number = 12,
volume = 126,
place = {United States},
year = {Wed Mar 28 00:00:00 EDT 2007},
month = {Wed Mar 28 00:00:00 EDT 2007}
}