Irradiation of organic solution surfaces with intense 248 nm laser light resulted in "jet" ejection with a distinct threshold, which was elucidated by a nanosecond imaging method. The threshold value increased as the boiling point of solvent increased, and the estimated temperature at the threshold was close to the boiling point in each system. The behavior is clearly ascribed to a photothermal process; explosive boiling of liquids causes the jet ejection. In time-resolved spectroscopic measurements, hot bands of solute fluorescence were clearly identified and heating dynamics was directly followed. Transient species involved in the jet ejection were excited singlet, triplet, and cationic states of solute molecules. The triplet-triplet annihilation process was confirmed, and the mechanism underlying the jet ejection are discussed in detail correlating the dynamic behavior of jet ejection with the temporal behavior of transient species.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry