Relaxation of H2O from its /04>- vibrational state in collisions with H2O, Ar, H2, N2, and O2.

We report rate coefficients at 293 K for the collisional relaxation of H2O molecules from the highly excited /04>(+/-) vibrational states in collisions with H2O, Ar, H2, N2, and O2. In our experiments, the mid R:04(-) state is populated by direct absorption of radiation from a pulsed dye laser tuned to approximately 719 nm. Evolution of the population in the (/04>(+/-)) levels is observed using the combination of a frequency-quadrupled Nd:YAG laser, which selectively photolyses H2O(/04>(+/-)), and a frequency-doubled dye laser, which observes the OH(v=0) produced by photodissociation via laser-induced fluorescence. The delay between the pulse from the pump laser and those from the photolysis and probe lasers was systematically varied to generate kinetic decays. The rate coefficients for relaxation of H2O(/04>(+/-)) obtained from these experiments, in units of cm3 molecule(-1) s(-1), are: k(H2O)=(4.1+/-1.2) x 10(-10), k(Ar)=(4.9+/-1.1) x 10(-12), k(H2)=(6.8+/-1.1) x 10(-12), k(N2)=(7.7+/-1.5) x 10(-12), k(O2)=(6.7+/-1.4) x 10(-12). The implications of these results for our previous reports of rate constants for the removal of H2O molecules in selected vibrational states by collisions with H atoms (P. W. Barnes et al., Faraday Discuss. Chem. Soc. 113, 167 (1999) and P. W. Barnes et al., J. Chem. Phys. 115, 4586 (2001).) are fully discussed.

[1]  Ian W. M. Smith,et al.  Rate coefficients for rotational energy transfer from the levels OH(X 2Π3/2, v = 1, ji = 1.5, 3.5–8.5) in collisions with He, Ar, N2 and HNO3 , 2002 .

[2]  Ian W. M. Smith,et al.  The chemical kinetics and dynamics of the prototypical reaction: OH + H2 → H2O + H , 2002 .

[3]  Ian W. M. Smith,et al.  The branching ratio between reaction and relaxation in the removal of H2O from its |04〉− vibrational state in collisions with H atoms , 2001 .

[4]  V. Vaida,et al.  Sequential Two-Photon Dissociation of Atmospheric Water , 2001 .

[5]  V. A. Savin,et al.  The near infrared, visible, and near ultraviolet overtone spectrum of water , 1999 .

[6]  Ian W. M. Smith,et al.  Rate coefficients for the reaction and relaxation of vibrationally excited H2O(|04〉−) with H atoms and H2O , 1998 .

[7]  Meez Islam,et al.  Relaxation within and from the (31/214151) and (3141/214251) Fermi dyads in acetylene: Vibrational energy transfer in collisions with C2H2, N2 and H2 , 1998 .

[8]  J. Tennyson,et al.  The potential energy surface of H2 16O , 1996 .

[9]  G. Flynn,et al.  Vibrational energy transfer , 1996 .

[10]  J. Tennyson,et al.  The potential energy surface of $H_{2}^{16}O$ , 1996 .

[11]  J. Tobiason,et al.  State-to-state relaxation of highly vibrationally excited acetylene by argon , 1994 .

[12]  R. Metz,et al.  Selectively breaking either bond in the bimolecular reaction of HOD with hydrogen atoms , 1993 .

[13]  P. Andresen,et al.  Photodissociation of water in the first absorption band: A prototype for dissociation on a repulsive potential energy surface , 1992 .

[14]  B. Orr,et al.  Rotationally resolved V–V transfer in C2D2/Ar collisions: Characterization of a vibrational bottleneck , 1991 .

[15]  J. L. Scott,et al.  State resolved photodissociation of vibrationally excited water: Rotations, stretching vibrations, and relative cross sections , 1991 .

[16]  B. Orr.  Time-resolved infrared–ultraviolet double-resonance spectroscopy of formaldehyde-d2 , 1990 .

[17]  R. Schinke,et al.  Photodissociation of vibrationally excited water in the first absorption band , 1989 .

[18]  E. Browell,et al.  Spectroscopy of water vapor in the 720-nm wavelength region - Line strengths, self-induced pressure broadenings and shifts, and temperature dependence of linewidths and shifts , 1989 .

[19]  D. E. Masturzo,et al.  Vibrational relaxation of H2O from 295 to 1020 K , 1989 .

[20]  A. G. Robiette,et al.  On the relationship of normal modes to local modes in molecular vibrations , 1985 .

[21]  M. Child.  Local Mode Overtone Spectra , 1985 .

[22]  G. Jursich,et al.  Vibrational relaxation of HF(v=3, 4, and 5) by H2, D2, CH4, CD4, and CO2 , 1984 .

[23]  I. Smith,et al.  Vibrational relaxation of HCN(002)a) , 1983 .

[24]  I. Watson,et al.  Local mode behavior: The Morse oscillator model , 1981 .

[25]  F. Hovis,et al.  Temperature dependence of vibrational energy transfer in NH3 and H2 18O , 1980 .

[26]  James T. Yardley,et al.  Introduction to Molecular Energy Transfer , 1980 .