title: Reverse intersystem crossing in rhodamines by near-infrared laser excitation.
abstract: The population of the long-lived first excited triplet state (T1) of a fluorescence dye represents a major limitation in single-molecule spectroscopy. Reverse intersystem crossing (ReISC) is one of the processes that may prevent considerable loss of luminescence. In the present quantum chemical study we have analyzed rhodamine A in aqueous environment. The T2 ⇝ S1 and T3 ⇝ S2 ReISC channels are predicted to be viable. The rate constant computed for the former channel is ≈2 × 10(6) s(-1). Hence, an excitation with suitable wavelength to one of the triplets should help repopulate the optically bright singlet state S1.
authors.affiliation: Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf , Universitätsstrasse 1, D-40225 Düsseldorf, Germany.
authors.forename: Christel M
authors.initials: CM
authors.lastname: Marian
authors.forename: Mihajlo
authors.initials: M
authors.lastname: Etinski
authors.forename: Vidisha
authors.initials: V
authors.lastname: Rai-Constapel