Resonance Enhanced Multiphoton Ionization Spectroscopy of ClO
ABSTRACT
We present isotopically selected, multiphoton ionisation spectra of the
ClO radical following excitation in the wavelength range 276-261 nm,
obtained using both a room temperature sample and under the
rotationally cold conditions prevailing in a pulsed molecular beam. In
both cases high resolution rotationally resolved spectra were obtained,
with the 'cold' molecular beam spectra showing discrete rovibrational
bands. Analysis of the rotational structure leads to the identification
of excited levels of ClO of 2Π
symmetry resonant at the two photon energy (72200 - 76200 cm-1).
These we deduce to possess very extended equilibrium bond lengths (R ~
2.4 Å), and thus associate with one or more ion pair states. Full
interpretation of the observed spectra is complicated by the effects of
additional, wavelength dependent intensity enhancements due to
predissociated levels of the A2Π
state accidentally resonant at the energy of one absorbed photon. We
also report an isotopically resolved room temperature 2+1 REMPI
spectrum, involving a progression of vibrational levels of the
previously documented C2Σ
- state of ClO. The observed C - X two photon transitions
are well reproduced using the known spectroscopic constants of these
two states.
This page was created by Martin Cooper, on the 3rd March 1997.