No abstract

Absorption and emission spectra are reported for YF isolated in Ne, Ar, and Kr matrices and the ground state is confirmed as 1Σ+. Calculated Franck–Condon intensities permit confident assignments of vibrational quantum numbers for most of the states but point to an anomaly in the red emission produced on excitation into the B̃ state. Lifetime studies in argon show that such excitation also depletes ∼90% of the ground state population and that the return requires ∼15 min. As explanation, the ã 3Δ state of YF is proposed as a metastable sink, with the longest lifetime yet reported for a triplet state in matrices. Evidence for direct b̃ 3φ←X̃ 1Σ+ absorption is also presented and this suggests that the ã 3Δ state lies within ∼200 cm−1 of the X̃ state. The lifetime of the ã state is a sensitive probe of coupling of YF to the lattice phonons and it decreases by four orders of magnitude for YF in neon and in a ’’tighter’’ second site in argon.

No abstract

No abstract

No abstract