Determination of subnanosecond fluorescence decays of chlorobenzene, tryptophan and the benzene-triethylamine exciplex using a nanosecond flashlamp

Variations in detection efficiency of halobenzenes studied by using gas chromatography/laser ionization mass spectrometry: correlation with excited-state lifetimes

“…In the current work the relative laser ionization efficiencies of the monohalogenated benzenes (fluorobenzene, chlorobenzene, bromobenzene, and iodobenzene) are compared under nanosecond and picosecond laser conditions. The series of halobenzenes has been chosen for study because, with the exception of fluorobenzene, they are known to have subnanosecond lifetimes (1,8,9). Gas chromatography /laser ionization mass spectrometry (GC/MS) (3,4,6) is used to determine relative ion yields.…”

Assignment of the B̃+ State of the Chlorobenzene Cation Using Photoinduced Rydberg Ionization (PIRI) Spectroscopy

“…In all, these experiments have inferred that the symmetry of the B̃ + state is 2 B 2 , though the proximity of the C̃ + state to the B̃ + state makes the assignment somewhat difficult. Fluorescence emission studies on the chlorobenzene cation and the calculations done so far suggest that the B̃ + state of the cation has a half-filled σ orbital (a σ-state). This suggestion is inferred because the fluorescence quantum yields of emission are very small (of the order of ≤10 -5 ), similar to benzene where fluorescence is also not observed and the B̃ + state is known to have σ character.…”

Photoinduced Polymerization of Haloaniline Studied by Liquid Beam-Multiphoton Ionization-Mass Spectroscopy

“…The ion distribution changes significantly when the pulse width of the excitation laser is elongated from a fs- to a ns-range: (1) significant reduction of the H(−NHC 6 H 4 −) n Br + intensities and (2) increase in the degree of polymerization for H(−NHC 6 H 4 −) n H + and H(−NHC 6 H 4 −) n OC 2 H 5 + . These findings indicate that the precursor of the polymerization reaction initiated by the ns-laser excitation has a characteristic reaction time longer than 200 fs but shorter than 5 ns; the first excited state of the solute PBA molecule is considered to be the precursor, as the lifetime of halobenzene is reported to be less than 50 ps . Note that interval two-photon absorption is longer than 50 ps in the laser-fluence range of the ns-laser used.…”

“…These findings indicate that the precursor of the polymerization reaction initiated by the ns-laser excitation has a characteristic reaction time longer than 200 fs but shorter than 5 ns; the first excited state of the solute PBA molecule is considered to be the precursor, as the lifetime of halobenzene is reported to be less than 50 ps. 28 Note that interval two-photon absorption is longer than 50 ps in the laser-fluence range of the ns-laser used.…”