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Multi-photon ionization and fragmentation of uracil: Neutral excited-state ring opening and hydration effects

Barc, B., Ryszka, M., Spurrell, J., Dampc, M., Limão-Vieira, P., Parajuli, R., Mason, Nigel, Eden, S. (2013) Multi-photon ionization and fragmentation of uracil: Neutral excited-state ring opening and hydration effects. Journal of Chemical Physics, 139 (24). (doi:10.1063/1.4851476) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)
Official URL
https://doi.org/10.1063/1.4851476

Abstract

Multi-photon ionization (MPI) of the RNA base uracil has been studied in the wavelength range 220-270 nm, coinciding with excitation to the S 2(ππ*) state. A fragment ion at m/z = 84 was produced by 2-photon absorption at wavelengths ≤232 nm and assigned to C 3H4N2O+ following CO abstraction. This ion has not been observed in alternative dissociative ionization processes (notably electron impact) and its threshold is close to recent calculations of the minimum activation energy for a ring opening conical intersection to a σ(n-π)π* closed shell state. Moreover, the predicted ring opening transition leaves a CO group at one end of the isomer, apparently vulnerable to abstraction. An MPI mass spectrum of uracil-water clusters is presented for the first time and compared with an equivalent dry measurement. Hydration enhances certain fragment ion pathways (particularly C 3H3NO+) but represses C3H 4N2O+ production. This indicates that hydrogen bonding to water stabilizes uracil with respect to neutral excited-state ring opening.

Item Type: Article
DOI/Identification number: 10.1063/1.4851476
Uncontrolled keywords: Closed shells, Conical intersection, Dissociative ionization, Electron impact, Fragment ions, Hydration effects, Multiphoton ionization, Wavelength ranges, Abstracting, Activation energy, Aromatic compounds, Excited states, Hydration, Hydrogen bonds, Ions, Mass spectrometry, Multiphoton processes, Photons, Photoionization, uracil, water, article, chemistry, conformation, photochemistry, photon, Molecular Conformation, Photochemical Processes, Photons, Uracil, Water
Divisions: Faculties > Sciences > School of Physical Sciences
Depositing User: Nigel Mason
Date Deposited: 16 Jul 2019 10:19 UTC
Last Modified: 16 Jul 2019 10:19 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/74713 (The current URI for this page, for reference purposes)
Mason, Nigel: https://orcid.org/0000-0002-4468-8324
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