title: Efficiency of the photoprocesses leading to singlet oxygen (1 delta g) generation by alpha-terthienyl: optical absorption, optoacoustic calorimetry and infrared luminescence studies.
abstract: The triplet energy of alpha-terthienyl has been determined by heavy atom-induced optical absorption: the value of 39.7 +/- 1.5 kcal/mol is consistent with earlier energy transfer work. Combining this result with calorimetric data from optoacoustic calorimetry indicates that intersystem crossing occurs with at least 90% efficiency in polar and non-polar solvents. The quantum yields for singlet oxygen formation via energy transfer from triplet alpha-terthienyl have been obtained from time-resolved measurements of its IR phosphorescence: these yields are in the 0.6-0.8 range in non-polar and polar (hydroxylic and non-hydroxylic) solvents.
authors.affiliation: Division of Chemistry, National Research Council of Canada, Ottawa.
authors.forename: J C
authors.initials: JC
authors.lastname: Scaiano
authors.forename: R W
authors.initials: RW
authors.lastname: Redmond
authors.forename: B
authors.initials: B
authors.lastname: Mehta
authors.forename: J T
authors.initials: JT
authors.lastname: Arnason
mesh_terms: D002151:Calorimetry; D007202:Indicators and Reagents; D049449:Luminescence; D010100:Oxygen / Q000737:chemistry*; D010777:Photochemistry; D026082:Singlet Oxygen; D013055:Spectrophotometry, Infrared; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D007202:Indicators and Reagents; D013876:Thiophenes; C019101:alpha-terthienyl; D026082:Singlet Oxygen; D010100:Oxygen