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RESEARCH PRODUCT
On the Intrinsic Population of the Lowest Triplet State of Thymine
Luis Serrano-andrésManuela MerchánJuan José Serrano-pérezRemedios González-luquesubject
Models Moleculareducation.field_of_studyPopulationMolecular ConformationQuantum yieldSurfaces Coatings and FilmsThymineWavelengthchemistry.chemical_compoundIntersystem crossingchemistrySinglet fissionMaterials ChemistrySinglet statePhysical and Theoretical ChemistryAtomic physicsTriplet stateeducationThyminedescription
The population of the lowest triplet state of thymine after near-UV irradiation has been established, on the basis of CASPT2//CASSCF quantum chemical calculations, to take place via three distinct intersystem crossing mechanisms from the initially populated singlet bright 1pipi* state. Two singlet-triplet crossings have been found along the minimum-energy path for ultrafast decay of the singlet state at 4.8 and 4.0 eV, involving the lowest 3npi* and 3pipi* states, respectively. Large spin-orbit coupling elements predict efficient intersystem crossing processes in both cases. Another mechanism involving energy transfer from the lowest 1npi* state with much larger spin-orbit coupling terms can also be proposed. The wavelength dependence measured for the triplet quantum yield of pyrimidine nucleobases is explained by the location and accessibility of the singlet-triplet crossing regions.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2007-10-12 | The Journal of Physical Chemistry B |