Photosensitised production of singlet oxygen, (Δ), in the unique 'heavy-atom' solvent, supercritical fluid xenon. Pressure dependence of electronic to vibrational energy conversion during quenching of (Δ) by xenon and by ground state oxygen

Autor:	Francis Wilkinson, Ayman A. Abdel-Shafi, David R. Worrall
Rok vydání:	2001
Předmět:	Quenching (fluorescence) Singlet oxygen General Physics and Astronomy chemistry.chemical_element Oxygen Supercritical fluid chemistry.chemical_compound Xenon Reaction rate constant chemistry Physical chemistry Singlet state Physical and Theoretical Chemistry Ground state
Zdroj:	Chemical Physics Letters. 343:273-280
ISSN:	0009-2614
DOI:	10.1016/s0009-2614(01)00727-8
Popis:	Photosensitised generation of singlet oxygen, O 2 * ( a 1 Δ g ) , in supercritical xenon, SCF-Xe at 325 K is reported for the first time. Rate constants for quenching by ground state oxygen, and by xenon, vary from 8.9±0.3 to 13±1×10 2 and from 7±1 to 4.4±0.5 dm 3 mol −1 s −1 , respectively, as the pressure increases from 7.8 to 44 MPa. The measured decay constant shows little temperature dependence in the range 295–325 K at 29.6 MPa. The extrapolated lifetime of O 2 * ( a 1 Δ g ) , expected in the absence of O 2 ( X 3 Σ g − ) , in SCF-Xe, at 325 K and 8.8 MPa is 22±3 ms . Explanations for observed variations are proposed and factors governing the decay of singlet oxygen in SCF-Xe are discussed.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::b0d0b37c55835f2aa72aba5de84984b8 https://doi.org/10.1016/s0009-2614(01)00727-8 Zobrazit plný text záznamu Full Text from ScienceDirect