https://doi.org/10.1140/epjd/e2003-00056-2
Two-photon laser-induced fluorescence of H2O and D2O molecules at ambient pressure
Laboratoire d'Ingénierie des Matériaux et des Hautes Pressions, CNRS,
Institut Galilée, Université Paris-Nord, 93430 Villetaneuse, France
Corresponding author: a kanaev@limhp.univ-paris13.fr
Received:
25
January
2002
Revised:
27
May
2002
Published online:
4
March
2003
We have carried out experiments of two-photon excitation of vapor phase H2O and D2O
molecules at atmospheric pressure. A narrow-band tunable UV OPO laser is used in the
experiments. Transient 
emission from the excited predissociating state is seen in
both cases. The complete 
fluorescence excitation spectrum in the spectral range
of 245–250 nm is measured and compared with theory. It is shown that the predissociation
rate increases with the rotational quantum number 
more strongly than with 
. No
perturbation effects on the measured LIF spectra are observed at a laser power density below
2 GW/cm2. Experimental results indicate a negligible contribution from both molecular
association and collisions with atmospheric gases. Only an extremely weak vibrational
progression belonging to the second positive system of N2 has been observed, which appears
to be due to energy and charge transfer in 
collisions.
PACS: 33.80.Rv – Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states) / 32.50.+d – Fluorescence, phosphorescence (including quenching) / 33.70.Fd – Absolute and relative line and band intensities
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003
