Ultrafast Decay Dynamics of 2-Hydroxypyridine Excited to S₁ Electronic State

The S_1 state decay dynamics of 2-hydroxypyridine following UV excitation at a wavelength range of 276.9-250.0 nm is investigated using femtosecond time-resolved photoelectron imaging technique. Based on pump wavelength dependence of the decay dynamics, a refined decay picture is proposed. At pump wavelength of 276.9 nm, the S_1 state is depopulated through intersystem crossing to lower triplet state(s). At 264.0 nm, both intersystem crossing to lower triplet state(s) and internal conversion to the ground state are in operation. At 250.0 nm, internal conversion to the ground state becomes dominated.