Measurement of ultraweak transitions in the visible region of molecular oxygen

Leeuwen, Nicola J. van; Kjaergaard, Henrik G.; Howard, Daryl L.; Wilson, Andrew

doi:10.1016/j.jms.2004.07.002

Cited by 23 publications

(16 citation statements)

References 14 publications

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“…Note that in this pressure regime the definition of the line mixing coefficients is still the one given in Eq. (18). For these elevated pressures the absorption coefficient becomes:…”

Section: Weak Line Mixing Effects In the Oxygen A-bandmentioning

confidence: 97%

“…In the past two decades there have been numerous studies focused upon the oxygen A-band [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Ritter and Wilkerson [5] measured the absorption profiles of 54 transitions within the O 2 A-band using tuneable dye laser spectroscopy and afterwards compared the adequacy of the fits of the measured spectral lines given by Voigt, Galatry, Rautian and Sobelman, and Berman lineshape profiles.…”

Section: Introductionmentioning

confidence: 99%

“…The authors modeled the broadening results using two rotational energy transfer scaling laws: EPGL-0 and ECS-P. Leeuwen et al [18] reported line positions, intensities, and Lorentzian linewidths for 12 P-branch transitions with J 00 values ranging from 34 to 45 using noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Spectroscopic lineshape study of the self-perturbed oxygen A-band

Predoi‐Cross

Hambrook

Keller

et al. 2008

Journal of Molecular Spectroscopy

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“…Note that in this pressure regime the definition of the line mixing coefficients is still the one given in Eq. (18). For these elevated pressures the absorption coefficient becomes:…”

Section: Weak Line Mixing Effects In the Oxygen A-bandmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spectroscopic lineshape study of the self-perturbed oxygen A-band

Predoi‐Cross

Hambrook

Keller

et al. 2008

Journal of Molecular Spectroscopy

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“…While that first realization was based on a fixed frequency Nd:YAG laser, there have been several attempts since then to make use of the extreme sensitivity by the development of instrumentations based on various types of tunable lasers [4][5][6][7][8][9][10][11][12][13]. The so far best Db detection sensitivity incorporating a tunable laser was recently demonstrated with a fiber-laser-based (FLB) NICE-OHMS system, yielding an Allan deviation of 5.6 × 10 −12 cm −1 Hz −1∕2 , which for an integration time of 10 s corresponds to 4 ppt of acetylene in an atmospheric pressure sample [14].…”

Section: Introductionmentioning

confidence: 99%

Doppler broadened noise-immune cavity-enhanced optical heterodyne molecular spectrometry: optimum modulation and demodulation conditions, cavity length, and modulation order

2014

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Doppler broadened noise-immune cavity-enhanced optical heterodyne molecular spectrometry (Db-NICE-OHMS) has been scrutinized with respect to modulation and demodulation conditions (encompassing the modulation frequency, ν m , the modulation index, β, and the detection phase, θ), the cavity length, L, and the modulation order, k (defined as ν m ∕ν FSR , where ν FSR is the free-spectral range of the cavity), primarily in the Doppler limit but also for two specific situations in the Voigt regime (for equal Doppler and homogeneous width and for purely Lorentzian broadened transitions), both in the absence and presence of optical saturation (the latter for the case in which the homogeneous broadening is smaller than the modulation frequency). It is found that, for a system with a given cavity length, the optimum conditions (i.e., those that produce the largest NICE-OHMS signal) for an unsaturated transition in the Doppler limit comprise ν m ∕Γ D 1.6 (where Γ D is the half-width at half-maximum of the Doppler width of the transition), β 1.3, and θ 0.78π. It is also found that the maximum is rather broad; the signal takes 95% of its maximum value for modulation frequencies in the entire 0.4 ≲ ν m ∕Γ D ≲ 2.4 range. When optical saturation sets in, θ shifts toward the dispersion phase. The optimum conditions encompass k > 1 whenever L > 0.35L D and 2.6L D for the dispersion and absorption modes of detection, respectively [where L D is a characteristic length given by c∕2Γ D ]. Similar conditions are found under pressure broadened conditions.

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“…The method has recently been further developed to be applicable also on pressure-broadened absorption features described by a Voigt profile 13 and it has been used to characterize weak rovibronic transitions in molecular oxygen. 14 In the present work, we apply NICE-OHMS to study the weak sixth overtone band of nitric oxide. In a previous paper we reported measurements of three rovibrational lines in the R branch of the 2 ⌸ 1/2 -2 ⌸ 1/2 subband.…”

Section: Introductionmentioning

confidence: 99%

Measurement of the sixth overtone band of nitric oxide, and its dipole moment function, using cavity-enhanced frequency modulation spectroscopy

Bood

McIlroy

Osborn

2006

The Journal of Chemical Physics

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We applied cavity-enhanced frequency modulation absorption spectroscopy (also known as noise-immune cavity-enhanced optical heterodyne molecular spectroscopy) to perform high-resolution spectroscopy of the sixth overtone band of nitric oxide near 797 nm. By using novel high-bandwidth balanced detectors, baseline variations caused by residual amplitude modulation were significantly reduced. The ultrahigh sensitivity (2 x 10(-10) cm(-1) minimum detectable absorption at 1 Hz detection bandwidth) of our spectrometer allowed accurate measurements of 15 individual line intensities of P- and R-branch transitions in the 2Pi(1/2)-2Pi(1/2) subband. A vibrational transition moment of 3.09(6) muD+/-13% and Herman-Wallis coefficients of a = -0.0078(26) and b = 0.001 25(45) were found by fitting the line intensities. Based on our measured transition moment, and those of other transitions from the literature, a new parametrization for the electric dipole moment function (EDMF) of nitric oxide, valid for 0.91 < or = r < or = 1.74 A, has been extracted. The residuals of this fit demonstrate that the derived EDMF is the most accurate representation to date of the dipole moment function. The new EDMF will be valuable for accurate intensity prediction of transitions that cannot be easily measured experimentally.

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Measurement of ultraweak transitions in the visible region of molecular oxygen

Cited by 23 publications

References 14 publications

Spectroscopic lineshape study of the self-perturbed oxygen A-band

Spectroscopic lineshape study of the self-perturbed oxygen A-band

Doppler broadened noise-immune cavity-enhanced optical heterodyne molecular spectrometry: optimum modulation and demodulation conditions, cavity length, and modulation order

Measurement of the sixth overtone band of nitric oxide, and its dipole moment function, using cavity-enhanced frequency modulation spectroscopy

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