Multi-photon UV photolysis of gaseous polycyclic aromatic hydrocarbons: Extinction spectra and dynamics

Show simple item record Walsh, Anton J. Ruth, Albert A. Gash, Edward W. Mansfield, Michael W. D. 2019-12-05T15:22:24Z 2019-12-05T15:22:24Z 2013-08-05
dc.identifier.citation Walsh, A. J., Ruth, A. A., Gash, E. W. and Mansfield, M. W. D. (2013) 'Multi-photon UV photolysis of gaseous polycyclic aromatic hydrocarbons: Extinction spectra and dynamics', The Journal of Chemical Physics, 139(5), 054304 (15 pp). doi: 10.1063/1.4816003 en
dc.identifier.volume 139 en
dc.identifier.issued 5 en
dc.identifier.startpage 1 en
dc.identifier.endpage 15 en
dc.identifier.issn 0021-9606
dc.identifier.doi 10.1063/1.4816003 en
dc.description.abstract The extinction spectra of static naphthalene and static biphenylene vapor, each buffered with a noble gas at room temperature, were measured as a function of time in the region between 390 and 850 nm after UV multi-photon laser photolysis at 308 nm. Employing incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS), the spectra were found to be unstructured with a general lack of isolated features suggesting that the extinction was not solely based on absorption but was in fact dominated by scattering from particles formed in the photolysis of the respective polycyclic aromatic hydrocarbon. Following UV multi-photon photolysis, the extinction dynamics of the static (unstirred) closed gas-phase system exhibits extraordinary quasi-periodic and complex oscillations with periods ranging from seconds to many minutes, persisting for up to several hours. Depending on buffer gas type and pressure, several types of dynamical responses could be generated (classified as types I, II, and III). They were studied as a function of temperature and chamber volume for different experimental conditions and possible explanations for the oscillations are discussed. A conclusive model for the observed phenomena has not been established. However, a number of key hypotheses have made based on the measurements in this publication: (a) Following the multi-photon UV photolysis of naphthalene (or biphenylene), particles are formed on a timescale not observable using IBBCEAS. (b) The observed temporal behavior cannot be described on basis of a chemical reaction scheme alone. (c) The pressure dependence of the system's responses is due to transport phenomena of particles in the chamber. (d) The size distribution and the refractive indices of particles are time dependent and evolve on a timescale of minutes to hours. The rate of particle coagulation, involving coalescent growth and particle agglomeration, affects the observed oscillations. (e) The walls of the chamber act as a sink. The wall conditions (which could not be quantitatively characterized) have a profound influence on the dynamics of the system and on its slow return to an equilibrium state. en
dc.description.sponsorship Enterprise Ireland (Basic Research Grant Scheme contract: SC/2003/96)); Higher Education Authority (HEA–PRTLI3 scheme) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher AIP Publishing en
dc.rights © 2013, AIP Publishing LLC. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in The Journal of Chemical Physics and may be found at en
dc.subject Organic compounds en
dc.subject Multiphoton spectra en
dc.subject Refractive index en
dc.subject Excited states en
dc.subject Chemical equilibrium en
dc.subject Photoexcitation en
dc.subject Molecule-photon collisions en
dc.subject Extinction coefficients en
dc.subject Photolysis en
dc.title Multi-photon UV photolysis of gaseous polycyclic aromatic hydrocarbons: Extinction spectra and dynamics en
dc.type Article (peer-reviewed) en
dc.internal.authorcontactother Albert Ruth, Physics, University College Cork, Cork, Ireland. +353-21-490-3000 Email: en
dc.internal.availability Full text available en 2019-12-05T15:11:16Z
dc.description.version Published Version en
dc.internal.rssid 241501473
dc.contributor.funder Enterprise Ireland en
dc.contributor.funder Higher Education Authority en
dc.contributor.funder Science Foundation Ireland en
dc.description.status Peer reviewed en
dc.identifier.journaltitle Journal of Chemical Physics en
dc.internal.copyrightchecked No
dc.internal.licenseacceptance Yes en
dc.internal.IRISemailaddress en
dc.internal.IRISemailaddress en
dc.identifier.articleid 54304 en
dc.relation.project info:eu-repo/grantAgreement/SFI/SFI Research Frontiers Programme (RFP)/11/RFP.1/PHY/3233/IE/Anti-Stokes fluorescence of organic dyes: potential new materials for laser cooling in solids/ en

Files in this item

This item appears in the following Collection(s)

Show simple item record

This website uses cookies. By using this website, you consent to the use of cookies in accordance with the UCC Privacy and Cookies Statement. For more information about cookies and how you can disable them, visit our Privacy and Cookies statement