Photoacoustic measurements of the vibrational relaxation of the selectively excited ozone (nu(3)) molecule in pure ozone and its binary mixtures withO-2, N-2, and noble gases
V. Zeninari et al., Photoacoustic measurements of the vibrational relaxation of the selectively excited ozone (nu(3)) molecule in pure ozone and its binary mixtures withO-2, N-2, and noble gases, J CHEM PHYS, 112(4), 2000, pp. 1835-1843
The vibrational-translational relaxation time of the nu(3) state of ozone w
as deduced from the phase shift of the photoacoustic detector signal relati
ve to the amplitude-modulated radiation of the CO2 laser used for excitatio
n of O-3. A special photoacoustic cell with a third electrode is used to el
iminate an instrumentation phase shift caused by inertia of the microphone
membrane. A three-level kinetic model of O-3 is presented and used to fit t
he experimental and calculated phase shifts to determine the vibrational re
laxation rate coefficients for pure O-3 and binary mixtures of O-3 with O-2
, N-2, and noble gases He, Ne, Ar, Kr, and Xe. These results are presented
and compared with experimental data obtained for O-3, O-3-O-2, and O-3-N-2
by fluorescence and double resonance techniques. Experimental data for nu(3
) state relaxation in binary mixtures with all noble atoms have been obtain
ed for the first time. These new results are compared with the simplest mod
el of interaction. Thus we obtain a very good agreement for the decrease of
constants with the increase of the colliding partner mass. (C) 2000 Americ
an Institute of Physics. [S0021-9606(00)00904-1].