Abstract

Two optical methods, cavity ring-down spectroscopy and photoacoustic spectroscopy, are applied to the measurement of the isotope ratio 18O/16O in water-vapor samples with a Nd3+:YAG pumped-dye laser. The combination band of (2ν 1 + ν 3) in the 960-nm region of water molecules is investigated for two standard water samples, the Vienna Standard Mean Ocean Water and the Standard Light Antarctic Precipitation. The results demonstrate that the two methods have the potential of compact systems for in-situ measurements of H2O isotope ratio in the environment.

© 2002 Optical Society of America

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References

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  1. J. Hoefs, Stable Isotope Geochemistry, 3rd ed. (Springer-Verlag, Berlin, 1987).
    [CrossRef]
  2. K. Lajitha, R. H. Michener, eds., Stable Isotopes in Ecology and Environmental Science (Blackwell, Oxford, 1994).
  3. H. P. Taylor, J. R. O’Neil, I. R. Kaplan, eds., Stable Isotope Geochemistry: A Tribute to Samuel Epstein, Special Publ. No. 3 (Geochemical Society, San Antonio, Tex., 1991).
  4. P. Fritz, J. Ch. Fontes, eds., The Terrestrial Environment, Vol. 1 of Handbook of Environmental Isotope Geochemistry (Elsevier, Amsterdam, 1980).
  5. J. Jouzel, G. L. Russel, R. J. Suozzo, R. D. Koster, J. W. C. White, W. S. Broecker, “Simulations of the HDO and H218O atmospheric cycles using the NASA GISS general circulation model: the seasonal cycle for present-day conditions,” J. Geophys. Res. 92, 14,739–14,760 (1987).
    [CrossRef]
  6. R. Gonfiantini, “Determinations of the oxygen isotope composition of natural waters” in Stable Isotope Hydrology, J. R. Gat, R. Gonfiantini, eds. (International Atomic Energy Agency, Vienna, 1981).
  7. A. O’Keefe, D. A. G. Deacon, “Cavity ring-down spectrometer for absorption measurements using pulsed laser sources,” Rev. Sci. Instrum. 59, 2544–2551 (1988).
    [CrossRef]
  8. G. Berden, R. Peeters, G. Meijer, “Cavity ring-down spectroscopy: experimental schemes and applications,” Int. Rev. Phys. Chem. 19, 565–607 (2000).
    [CrossRef]
  9. A. O’Keefe, “Integrated cavity output analysis of ultra-weak absorption,” Chem. Phys. Lett. 293, 331–336 (1998).
    [CrossRef]
  10. A. O’Keefe, J. J. Scherer, J. B. Paul, “CW integrated cavity output spectroscopy,” Chem. Phys. Lett. 307, 343–349 (1999).
    [CrossRef]
  11. The HITRAN 2000 molecular spectroscopic database can be downloaded from http://cfa-www.harvard.edu/HITRAN/ or ftp://cfa.ftp.harvard.edu/pub/HITRAN/ .
  12. H. Naus, A. de Lange, W. Ubachs, “b1Σ+g-X3-Σ-g(0,0) band of oxygen isotopomers in relation to tests of the symmetrization postulate in 16O2” Phys. Rev. A 56, 4755–4763 (1997).
    [CrossRef]
  13. S. S. Brown, R. W. Wilson, A. R. Ravishankara, “Absolute intensities for third and fourth overtone absorptions in HNO3 and H2O2 measured by cavity ring-down spectroscopy,” J. Phys. Chem. A 104, 4976–4983 (2000).
    [CrossRef]
  14. A. Rosencwaig, Photoacoustics and Photoacoustic Spectroscopy (Wiley, New York, 1980).
  15. M. Feher, Y. Jiang, J. P. Maier, A. Miklos, “Optoacoustic trace gas monitoring with near-infrared diode lasers,” Appl. Opt. 33, 1655–1658 (1994).
    [CrossRef]
  16. Y. Matsumi, M. Kishigami, N. Tanaka, M. Kawasaki, G. Inoue, “Isotope 18O/16O ratio measurements of water vapor by use of photoacoustic spectroscopy,” Appl. Opt. 37, 6558–6562 (1998).
    [CrossRef]
  17. Y. Ninomiya, S. Hashimoto, M. Kawasaki, T. J. Wallington, “Cavity ring-down study of BrO radicals: kinetics of the Br+O3 reaction and rate of relaxation of vibrationally excited BrO by collisions with N2 and O2,” Int. J. Chem. Kinet. 32, 125–130 (2000).
    [CrossRef]
  18. J. T. Hodges, J. P. Looney, R. D. van Zee, “Laser bandwidth effects in quantitative cavity ring-down spectroscopy,” Appl. Opt. 35, 4112–4116 (1996).
    [CrossRef] [PubMed]
  19. S.-C. Xu, D.-X. Dai, J.-C. Xie, G.-H. Sha, C.-H. Zhang, “Quantitative measurements of O2 b ← X(2,1,0 ← 0) bands by using cavity ring-down spectroscopy,” Chem. Phys. Lett. 303, 171–175 (1999).
    [CrossRef]
  20. J. B. Paul, C. P. Collier, R. J. Saykally, J. J. Scherer, A. O’Keefe, “Direct measurement of water cluster concentrations by infrared cavity ringdown laser absorption spectroscopy,” J. Phys. Chem. A 101, 5211–5214 (1997).
    [CrossRef]
  21. B. E. Grossmann, E. V. Browell, “Water vapor line broadening and shifting by air, nitrogen, and argon in the 720-nm wavelength region,” J. Mol. Spectrosc. 138, 562–595 (1989).
    [CrossRef]

2000

G. Berden, R. Peeters, G. Meijer, “Cavity ring-down spectroscopy: experimental schemes and applications,” Int. Rev. Phys. Chem. 19, 565–607 (2000).
[CrossRef]

S. S. Brown, R. W. Wilson, A. R. Ravishankara, “Absolute intensities for third and fourth overtone absorptions in HNO3 and H2O2 measured by cavity ring-down spectroscopy,” J. Phys. Chem. A 104, 4976–4983 (2000).
[CrossRef]

Y. Ninomiya, S. Hashimoto, M. Kawasaki, T. J. Wallington, “Cavity ring-down study of BrO radicals: kinetics of the Br+O3 reaction and rate of relaxation of vibrationally excited BrO by collisions with N2 and O2,” Int. J. Chem. Kinet. 32, 125–130 (2000).
[CrossRef]

1999

S.-C. Xu, D.-X. Dai, J.-C. Xie, G.-H. Sha, C.-H. Zhang, “Quantitative measurements of O2 b ← X(2,1,0 ← 0) bands by using cavity ring-down spectroscopy,” Chem. Phys. Lett. 303, 171–175 (1999).
[CrossRef]

A. O’Keefe, J. J. Scherer, J. B. Paul, “CW integrated cavity output spectroscopy,” Chem. Phys. Lett. 307, 343–349 (1999).
[CrossRef]

1998

1997

J. B. Paul, C. P. Collier, R. J. Saykally, J. J. Scherer, A. O’Keefe, “Direct measurement of water cluster concentrations by infrared cavity ringdown laser absorption spectroscopy,” J. Phys. Chem. A 101, 5211–5214 (1997).
[CrossRef]

H. Naus, A. de Lange, W. Ubachs, “b1Σ+g-X3-Σ-g(0,0) band of oxygen isotopomers in relation to tests of the symmetrization postulate in 16O2” Phys. Rev. A 56, 4755–4763 (1997).
[CrossRef]

1996

1994

1989

B. E. Grossmann, E. V. Browell, “Water vapor line broadening and shifting by air, nitrogen, and argon in the 720-nm wavelength region,” J. Mol. Spectrosc. 138, 562–595 (1989).
[CrossRef]

1988

A. O’Keefe, D. A. G. Deacon, “Cavity ring-down spectrometer for absorption measurements using pulsed laser sources,” Rev. Sci. Instrum. 59, 2544–2551 (1988).
[CrossRef]

1987

J. Jouzel, G. L. Russel, R. J. Suozzo, R. D. Koster, J. W. C. White, W. S. Broecker, “Simulations of the HDO and H218O atmospheric cycles using the NASA GISS general circulation model: the seasonal cycle for present-day conditions,” J. Geophys. Res. 92, 14,739–14,760 (1987).
[CrossRef]

Berden, G.

G. Berden, R. Peeters, G. Meijer, “Cavity ring-down spectroscopy: experimental schemes and applications,” Int. Rev. Phys. Chem. 19, 565–607 (2000).
[CrossRef]

Broecker, W. S.

J. Jouzel, G. L. Russel, R. J. Suozzo, R. D. Koster, J. W. C. White, W. S. Broecker, “Simulations of the HDO and H218O atmospheric cycles using the NASA GISS general circulation model: the seasonal cycle for present-day conditions,” J. Geophys. Res. 92, 14,739–14,760 (1987).
[CrossRef]

Browell, E. V.

B. E. Grossmann, E. V. Browell, “Water vapor line broadening and shifting by air, nitrogen, and argon in the 720-nm wavelength region,” J. Mol. Spectrosc. 138, 562–595 (1989).
[CrossRef]

Brown, S. S.

S. S. Brown, R. W. Wilson, A. R. Ravishankara, “Absolute intensities for third and fourth overtone absorptions in HNO3 and H2O2 measured by cavity ring-down spectroscopy,” J. Phys. Chem. A 104, 4976–4983 (2000).
[CrossRef]

Collier, C. P.

J. B. Paul, C. P. Collier, R. J. Saykally, J. J. Scherer, A. O’Keefe, “Direct measurement of water cluster concentrations by infrared cavity ringdown laser absorption spectroscopy,” J. Phys. Chem. A 101, 5211–5214 (1997).
[CrossRef]

Dai, D.-X.

S.-C. Xu, D.-X. Dai, J.-C. Xie, G.-H. Sha, C.-H. Zhang, “Quantitative measurements of O2 b ← X(2,1,0 ← 0) bands by using cavity ring-down spectroscopy,” Chem. Phys. Lett. 303, 171–175 (1999).
[CrossRef]

de Lange, A.

H. Naus, A. de Lange, W. Ubachs, “b1Σ+g-X3-Σ-g(0,0) band of oxygen isotopomers in relation to tests of the symmetrization postulate in 16O2” Phys. Rev. A 56, 4755–4763 (1997).
[CrossRef]

Deacon, D. A. G.

A. O’Keefe, D. A. G. Deacon, “Cavity ring-down spectrometer for absorption measurements using pulsed laser sources,” Rev. Sci. Instrum. 59, 2544–2551 (1988).
[CrossRef]

Feher, M.

Grossmann, B. E.

B. E. Grossmann, E. V. Browell, “Water vapor line broadening and shifting by air, nitrogen, and argon in the 720-nm wavelength region,” J. Mol. Spectrosc. 138, 562–595 (1989).
[CrossRef]

Hashimoto, S.

Y. Ninomiya, S. Hashimoto, M. Kawasaki, T. J. Wallington, “Cavity ring-down study of BrO radicals: kinetics of the Br+O3 reaction and rate of relaxation of vibrationally excited BrO by collisions with N2 and O2,” Int. J. Chem. Kinet. 32, 125–130 (2000).
[CrossRef]

Hodges, J. T.

Hoefs, J.

J. Hoefs, Stable Isotope Geochemistry, 3rd ed. (Springer-Verlag, Berlin, 1987).
[CrossRef]

Inoue, G.

Jiang, Y.

Jouzel, J.

J. Jouzel, G. L. Russel, R. J. Suozzo, R. D. Koster, J. W. C. White, W. S. Broecker, “Simulations of the HDO and H218O atmospheric cycles using the NASA GISS general circulation model: the seasonal cycle for present-day conditions,” J. Geophys. Res. 92, 14,739–14,760 (1987).
[CrossRef]

Kawasaki, M.

Y. Ninomiya, S. Hashimoto, M. Kawasaki, T. J. Wallington, “Cavity ring-down study of BrO radicals: kinetics of the Br+O3 reaction and rate of relaxation of vibrationally excited BrO by collisions with N2 and O2,” Int. J. Chem. Kinet. 32, 125–130 (2000).
[CrossRef]

Y. Matsumi, M. Kishigami, N. Tanaka, M. Kawasaki, G. Inoue, “Isotope 18O/16O ratio measurements of water vapor by use of photoacoustic spectroscopy,” Appl. Opt. 37, 6558–6562 (1998).
[CrossRef]

Kishigami, M.

Koster, R. D.

J. Jouzel, G. L. Russel, R. J. Suozzo, R. D. Koster, J. W. C. White, W. S. Broecker, “Simulations of the HDO and H218O atmospheric cycles using the NASA GISS general circulation model: the seasonal cycle for present-day conditions,” J. Geophys. Res. 92, 14,739–14,760 (1987).
[CrossRef]

Looney, J. P.

Maier, J. P.

Matsumi, Y.

Meijer, G.

G. Berden, R. Peeters, G. Meijer, “Cavity ring-down spectroscopy: experimental schemes and applications,” Int. Rev. Phys. Chem. 19, 565–607 (2000).
[CrossRef]

Miklos, A.

Naus, H.

H. Naus, A. de Lange, W. Ubachs, “b1Σ+g-X3-Σ-g(0,0) band of oxygen isotopomers in relation to tests of the symmetrization postulate in 16O2” Phys. Rev. A 56, 4755–4763 (1997).
[CrossRef]

Ninomiya, Y.

Y. Ninomiya, S. Hashimoto, M. Kawasaki, T. J. Wallington, “Cavity ring-down study of BrO radicals: kinetics of the Br+O3 reaction and rate of relaxation of vibrationally excited BrO by collisions with N2 and O2,” Int. J. Chem. Kinet. 32, 125–130 (2000).
[CrossRef]

O’Keefe, A.

A. O’Keefe, J. J. Scherer, J. B. Paul, “CW integrated cavity output spectroscopy,” Chem. Phys. Lett. 307, 343–349 (1999).
[CrossRef]

A. O’Keefe, “Integrated cavity output analysis of ultra-weak absorption,” Chem. Phys. Lett. 293, 331–336 (1998).
[CrossRef]

J. B. Paul, C. P. Collier, R. J. Saykally, J. J. Scherer, A. O’Keefe, “Direct measurement of water cluster concentrations by infrared cavity ringdown laser absorption spectroscopy,” J. Phys. Chem. A 101, 5211–5214 (1997).
[CrossRef]

A. O’Keefe, D. A. G. Deacon, “Cavity ring-down spectrometer for absorption measurements using pulsed laser sources,” Rev. Sci. Instrum. 59, 2544–2551 (1988).
[CrossRef]

Paul, J. B.

A. O’Keefe, J. J. Scherer, J. B. Paul, “CW integrated cavity output spectroscopy,” Chem. Phys. Lett. 307, 343–349 (1999).
[CrossRef]

J. B. Paul, C. P. Collier, R. J. Saykally, J. J. Scherer, A. O’Keefe, “Direct measurement of water cluster concentrations by infrared cavity ringdown laser absorption spectroscopy,” J. Phys. Chem. A 101, 5211–5214 (1997).
[CrossRef]

Peeters, R.

G. Berden, R. Peeters, G. Meijer, “Cavity ring-down spectroscopy: experimental schemes and applications,” Int. Rev. Phys. Chem. 19, 565–607 (2000).
[CrossRef]

Ravishankara, A. R.

S. S. Brown, R. W. Wilson, A. R. Ravishankara, “Absolute intensities for third and fourth overtone absorptions in HNO3 and H2O2 measured by cavity ring-down spectroscopy,” J. Phys. Chem. A 104, 4976–4983 (2000).
[CrossRef]

Rosencwaig, A.

A. Rosencwaig, Photoacoustics and Photoacoustic Spectroscopy (Wiley, New York, 1980).

Russel, G. L.

J. Jouzel, G. L. Russel, R. J. Suozzo, R. D. Koster, J. W. C. White, W. S. Broecker, “Simulations of the HDO and H218O atmospheric cycles using the NASA GISS general circulation model: the seasonal cycle for present-day conditions,” J. Geophys. Res. 92, 14,739–14,760 (1987).
[CrossRef]

Saykally, R. J.

J. B. Paul, C. P. Collier, R. J. Saykally, J. J. Scherer, A. O’Keefe, “Direct measurement of water cluster concentrations by infrared cavity ringdown laser absorption spectroscopy,” J. Phys. Chem. A 101, 5211–5214 (1997).
[CrossRef]

Scherer, J. J.

A. O’Keefe, J. J. Scherer, J. B. Paul, “CW integrated cavity output spectroscopy,” Chem. Phys. Lett. 307, 343–349 (1999).
[CrossRef]

J. B. Paul, C. P. Collier, R. J. Saykally, J. J. Scherer, A. O’Keefe, “Direct measurement of water cluster concentrations by infrared cavity ringdown laser absorption spectroscopy,” J. Phys. Chem. A 101, 5211–5214 (1997).
[CrossRef]

Sha, G.-H.

S.-C. Xu, D.-X. Dai, J.-C. Xie, G.-H. Sha, C.-H. Zhang, “Quantitative measurements of O2 b ← X(2,1,0 ← 0) bands by using cavity ring-down spectroscopy,” Chem. Phys. Lett. 303, 171–175 (1999).
[CrossRef]

Suozzo, R. J.

J. Jouzel, G. L. Russel, R. J. Suozzo, R. D. Koster, J. W. C. White, W. S. Broecker, “Simulations of the HDO and H218O atmospheric cycles using the NASA GISS general circulation model: the seasonal cycle for present-day conditions,” J. Geophys. Res. 92, 14,739–14,760 (1987).
[CrossRef]

Tanaka, N.

Ubachs, W.

H. Naus, A. de Lange, W. Ubachs, “b1Σ+g-X3-Σ-g(0,0) band of oxygen isotopomers in relation to tests of the symmetrization postulate in 16O2” Phys. Rev. A 56, 4755–4763 (1997).
[CrossRef]

van Zee, R. D.

Wallington, T. J.

Y. Ninomiya, S. Hashimoto, M. Kawasaki, T. J. Wallington, “Cavity ring-down study of BrO radicals: kinetics of the Br+O3 reaction and rate of relaxation of vibrationally excited BrO by collisions with N2 and O2,” Int. J. Chem. Kinet. 32, 125–130 (2000).
[CrossRef]

White, J. W. C.

J. Jouzel, G. L. Russel, R. J. Suozzo, R. D. Koster, J. W. C. White, W. S. Broecker, “Simulations of the HDO and H218O atmospheric cycles using the NASA GISS general circulation model: the seasonal cycle for present-day conditions,” J. Geophys. Res. 92, 14,739–14,760 (1987).
[CrossRef]

Wilson, R. W.

S. S. Brown, R. W. Wilson, A. R. Ravishankara, “Absolute intensities for third and fourth overtone absorptions in HNO3 and H2O2 measured by cavity ring-down spectroscopy,” J. Phys. Chem. A 104, 4976–4983 (2000).
[CrossRef]

Xie, J.-C.

S.-C. Xu, D.-X. Dai, J.-C. Xie, G.-H. Sha, C.-H. Zhang, “Quantitative measurements of O2 b ← X(2,1,0 ← 0) bands by using cavity ring-down spectroscopy,” Chem. Phys. Lett. 303, 171–175 (1999).
[CrossRef]

Xu, S.-C.

S.-C. Xu, D.-X. Dai, J.-C. Xie, G.-H. Sha, C.-H. Zhang, “Quantitative measurements of O2 b ← X(2,1,0 ← 0) bands by using cavity ring-down spectroscopy,” Chem. Phys. Lett. 303, 171–175 (1999).
[CrossRef]

Zhang, C.-H.

S.-C. Xu, D.-X. Dai, J.-C. Xie, G.-H. Sha, C.-H. Zhang, “Quantitative measurements of O2 b ← X(2,1,0 ← 0) bands by using cavity ring-down spectroscopy,” Chem. Phys. Lett. 303, 171–175 (1999).
[CrossRef]

Appl. Opt.

Chem. Phys. Lett.

S.-C. Xu, D.-X. Dai, J.-C. Xie, G.-H. Sha, C.-H. Zhang, “Quantitative measurements of O2 b ← X(2,1,0 ← 0) bands by using cavity ring-down spectroscopy,” Chem. Phys. Lett. 303, 171–175 (1999).
[CrossRef]

A. O’Keefe, “Integrated cavity output analysis of ultra-weak absorption,” Chem. Phys. Lett. 293, 331–336 (1998).
[CrossRef]

A. O’Keefe, J. J. Scherer, J. B. Paul, “CW integrated cavity output spectroscopy,” Chem. Phys. Lett. 307, 343–349 (1999).
[CrossRef]

Int. J. Chem. Kinet.

Y. Ninomiya, S. Hashimoto, M. Kawasaki, T. J. Wallington, “Cavity ring-down study of BrO radicals: kinetics of the Br+O3 reaction and rate of relaxation of vibrationally excited BrO by collisions with N2 and O2,” Int. J. Chem. Kinet. 32, 125–130 (2000).
[CrossRef]

Int. Rev. Phys. Chem.

G. Berden, R. Peeters, G. Meijer, “Cavity ring-down spectroscopy: experimental schemes and applications,” Int. Rev. Phys. Chem. 19, 565–607 (2000).
[CrossRef]

J. Geophys. Res.

J. Jouzel, G. L. Russel, R. J. Suozzo, R. D. Koster, J. W. C. White, W. S. Broecker, “Simulations of the HDO and H218O atmospheric cycles using the NASA GISS general circulation model: the seasonal cycle for present-day conditions,” J. Geophys. Res. 92, 14,739–14,760 (1987).
[CrossRef]

J. Mol. Spectrosc.

B. E. Grossmann, E. V. Browell, “Water vapor line broadening and shifting by air, nitrogen, and argon in the 720-nm wavelength region,” J. Mol. Spectrosc. 138, 562–595 (1989).
[CrossRef]

J. Phys. Chem. A

J. B. Paul, C. P. Collier, R. J. Saykally, J. J. Scherer, A. O’Keefe, “Direct measurement of water cluster concentrations by infrared cavity ringdown laser absorption spectroscopy,” J. Phys. Chem. A 101, 5211–5214 (1997).
[CrossRef]

S. S. Brown, R. W. Wilson, A. R. Ravishankara, “Absolute intensities for third and fourth overtone absorptions in HNO3 and H2O2 measured by cavity ring-down spectroscopy,” J. Phys. Chem. A 104, 4976–4983 (2000).
[CrossRef]

Phys. Rev. A

H. Naus, A. de Lange, W. Ubachs, “b1Σ+g-X3-Σ-g(0,0) band of oxygen isotopomers in relation to tests of the symmetrization postulate in 16O2” Phys. Rev. A 56, 4755–4763 (1997).
[CrossRef]

Rev. Sci. Instrum.

A. O’Keefe, D. A. G. Deacon, “Cavity ring-down spectrometer for absorption measurements using pulsed laser sources,” Rev. Sci. Instrum. 59, 2544–2551 (1988).
[CrossRef]

Other

R. Gonfiantini, “Determinations of the oxygen isotope composition of natural waters” in Stable Isotope Hydrology, J. R. Gat, R. Gonfiantini, eds. (International Atomic Energy Agency, Vienna, 1981).

J. Hoefs, Stable Isotope Geochemistry, 3rd ed. (Springer-Verlag, Berlin, 1987).
[CrossRef]

K. Lajitha, R. H. Michener, eds., Stable Isotopes in Ecology and Environmental Science (Blackwell, Oxford, 1994).

H. P. Taylor, J. R. O’Neil, I. R. Kaplan, eds., Stable Isotope Geochemistry: A Tribute to Samuel Epstein, Special Publ. No. 3 (Geochemical Society, San Antonio, Tex., 1991).

P. Fritz, J. Ch. Fontes, eds., The Terrestrial Environment, Vol. 1 of Handbook of Environmental Isotope Geochemistry (Elsevier, Amsterdam, 1980).

A. Rosencwaig, Photoacoustics and Photoacoustic Spectroscopy (Wiley, New York, 1980).

The HITRAN 2000 molecular spectroscopic database can be downloaded from http://cfa-www.harvard.edu/HITRAN/ or ftp://cfa.ftp.harvard.edu/pub/HITRAN/ .

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Figures (4)

Fig. 1
Fig. 1

Temporal decay of the CRD signals: H2 16O 4.24 Torr with 247.3 Torr of N2 buffer gas: (a) at 10518.85 cm-1 for off-resonance with H2 16O overtone absorption line center by 0.32 cm-1, ring-down time τ = 3.95 × 10-6 s; (b) at 10518.48 cm-1 for off-resonant with H2 16O absorption line center by 0.050 cm-1, τ = 3.63 × 10-6 s; (c) at 10518.53 cm-1 for on-resonance with the water-absorption line, τ = 3.30 × 10-6 s. Single-exponential decay curves are fitted in a temporal range of 2–8 µs. The initial hump is caused by scattered laser light. The inset shows a nonexponential decay for H2 16O 5.0 Torr without N2 buffer gas added.

Fig. 2
Fig. 2

Detailed photoacoustic spectra of the combination band of (2v1 + v3) in the 950-nm wavelength region for V-SMOW and H2 18O-enriched water samples. Absorption lines marked by the asterisks indicate H2 18O lines.

Fig. 3
Fig. 3

Linear correlation of water-absorption line strengths measured by CRDS and PAS with respect to those taken from the HITRAN database.11 solid circles, CRD signal; and open circles, PAS signal. Wavelength range of measurement, λ = 948–952 nm.

Fig. 4
Fig. 4

Typical photoacoustic and CRD spectra for the V-SMOW sample. The assignments of Line 1 (H2 18O) and Line 2 (H2 16O) are listed in Table 1. The smooth curve is a best-fitted curve with the Voigt profile function, the parameters of which are described in the text.

Tables (1)

Tables Icon

Table 1 Assignment and Intensities of Water-Vapor Lines from HITRAN11

Equations (2)

Equations on this page are rendered with MathJax. Learn more.

δ18O=1000R2-R1/R1,
δ18OV-SMOW=1000 RSLAP-RV-SMOW/RV-SMOW,

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