Fluorescence Excitation Spectrum of OClO (òA₂)

Abstract

The fluorescence excitation (FE) spectrum for the Ã2A2 ↔ X̃2B1 transition of OClO cooled in supersonic jet expansions has been obtained for the first time from the origin band at 476 nm up to 355 nm. Despite rapid predissociation of the excited OClO molecules, the fluorescence emission is strong enough to give the FE spectrum with a high signal-to-noise ratio. The present FE spectrum shows the much lower rotational temperature and hence better state resolution than seen in previously reported spectra, demonstrating that it can be used as a convenient spectroscopic tool for the state and mode selection in the photodissociation dynamics studies. The FE spectroscopy can be also applied for the high-resolution spectroscopy and various kinetic studies on the OClO molecules.

Vibrational and Electronic Energy Levels of Polyatomic Transient Molecules. Supplement B

“…Irradiation at 440 nm results in the formation of FeϩD 2 . 1,2 T 0 ϭ9530(180) gas PE 3 T 0 ϭ11497(10) gas b -ã 465-1049 nm AB 1,3,27,44 LMR 21 LF 33,38,40,42,43 DL [47][48][49][50] Vib. sym.…”

“…͑0,14,0͒ϭ4.6͑1͒ s LF 9,39 ͑0,16,0͒ϭ1.3͑3͒ s LF 11 3.8͑3͒ s LF 39 B 010 ϭ8.59(4) DL 47 C 2v Structure: AB 3,29,31 T 0 ϭ3147(5) gas b -ã 465-1049 nm AB 1,3,27,28,44 LMR 21,26,30 PE 23,24 LF 32,38,40,42,43,45 SEP 32,34 DL[47][48][49][50] …”

Unexpectedly large O37ClO/O35ClO intensity ratios of the fluorescence from the low-energy vibrational levels of OClO (Ã 2A2)

“…But, no vibrational level shows the unusual isotopic effect at the higher energies than those covered in this work. 12 Many examples of the isotope effect in the decay rates of the electronically excited states have been reported. 19 Most of the cases are for the H/D isotopes and have been explained in terms of the more rapid tunneling of H atoms through the barrier than D atoms.…”

“…12 In short, the OClO mixture in He, kept at the pressure of 1 atm, was expanded through a 0.5 mmdiameter nozzle, which was driven with a homemade driver. The visible wavelengths spanning 480 to 400 nm were directly generated with a pulsed dye laser pumped with a Q-switched Nd:YAG laser.…”