Hyperfine Level Dependence of the Pressure Broadening of CH3I Rotational Transitions in the v6 = 1 Vibrational State

Belli, S.; Buffa, G.; Lieto, A. Di; Minguzzi, P.; Tarrini, O.; Tonelli, M.

doi:10.1006/jmsp.2000.8106

Cited by 18 publications

(13 citation statements)

References 19 publications

(23 reference statements)

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“…In the present work, the experimental conditions do not allow differentiating the hyperfine components. Therefore, we did not compare our self-broadening coefficients with those of Belli et al [17] . We therefore compared the self-broadening coefficients measured in this work with the only data available in the literature, i.e.…”

Section: Comparison With Previous Workmentioning

confidence: 95%

“…This molecule was the subject of numerous microwave and infrared studies focused on the ground and various excited states, and several combination bands (see [ 15,16 and references therein] for an exhaustive review on the spectroscopic parameters of CH 3 I). To the best of our knowledge, only two studies dealt with the measurement of line broadening coefficients [17,18] . Self-broadening parameters of 6 hyperfine components of the ( J = 10 → 9, K l = 9) rotational transitions in the v 6 = 1 excited vibrational state were accurately measured using Doppler-free double-resonance spectroscopy [17] , and room temperature self-, N 2 -and O 2 -broadening coefficients were measured for over 100 lines in five Q -branches of the ν 5 perpendicular band at 7 μm using diode laser absorption spectroscopy [18] .…”

Section: Introductionmentioning

confidence: 99%

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Self and N2 collisional broadening of rovibrational lines in the ν6 band of methyl iodide (12CH3I) at room temperature: The J and K dependence

Attafi

Hassen

Aroui

et al. 2019

Journal of Quantitative Spectroscopy and Radiative Transfer

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Following our recent study devoted to measurements of intensities of rovibrational lines in the ν 6 band of methyl iodide (12 CH 3 I) centered at 892.918 cm −1 , room temperature infrared spectra of methyl iodide diluted in nitrogen at fourteen total pressures between 20 and 300 hPa have been recorded using the Fourier transform spectrometer Bruker IF125HR located at the LISA facility in Créteil. Three hundred and forty six N 2-broadening coefficients of methyl iodide rovibrational lines have been measured in the 824-951 cm −1 spectral range using mono-spectrum non-linear least squares fitting of Voigt profiles. Pressure-induced line shifts were not needed to fit the spectra to the noise level and line mixing effects could be neglected. Six hundred and eight self-broadening coefficients have also been measured in the same spectral range using the pure methyl iodide spectra recorded in our previous work. The measured self-broadening coefficients range from 0.1460 to 0.3786 cm − 1 atm −1 and the N 2-broadening coefficients range from 0.0723 to 0.1481 cm −1 atm − 1 at 295 K. The average accuracy on the measured self-and N 2-broadening coefficients was estimated to 3%. Comparisons with measurements reported in the literature for the ν 5 band of CH 3 I shows a satisfactory agreement with average differences of 7% and 4% for the self-and N 2-broadening coefficients, respectively. The J and K rotational dependences of these coefficients have been observed and the latter modeled using an empirical polynomial expansion. On average, the empirical expression reproduces the measured self-and N 2-broadening coefficients to within 3% and 4%, respectively. The data obtained in the present work represent a significant contribution to the determination of broadening coefficients of CH 3 I and complement the list of line positions and intensities generated in our previous work, thus providing useful spectroscopic information for atmospheric remote sensing and industrial detection of CH 3 I.

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Section: Comparison With Previous Workmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Self and N2 collisional broadening of rovibrational lines in the ν6 band of methyl iodide (12CH3I) at room temperature: The J and K dependence

Attafi

Hassen

Aroui

et al. 2019

Journal of Quantitative Spectroscopy and Radiative Transfer

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“…Its rotational spectrum in the ground and in its first excited vibrational states was investigated in detail using microwave [7][8][9], Doppler-free double resonance techniques [10,11]. This molecule was also the subject of numerous infrared studies which concern the m 1 [12], m 3 [13], m 4 [14], m 5 [15], m 2 , m 5 and m 3 + m 6 band system [16], m 6 [17][18][19][20][21][22], and 2m 3 [23] bands and several combination bands in the 2800 cm À1 spectral region [24].…”

Section: Introductionmentioning

confidence: 99%

New analysis of the ν6 and 2ν3 bands of methyl iodide (CH3I)

Perrin

Haykal

Kwabia-Tchana

et al. 2016

Journal of Molecular Spectroscopy

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a b s t r a c tA new rovibrational study of the m 6 band of methyl iodide was conducted to obtain a rather complete line list. A new analysis of line positions was accomplished. The spectrum of this band has been first recorded using the Bruker IFS125HR Fourier transform spectrometer (FTS) at the AILES beamline of the SOLEIL Synchrotron facility and later with the Bruker IFS125HR FTS located at the LISA facility in Créteil.Altogether, about 10,000 lines were assigned for the m 6 and 2m 3 bands up to high quantum numbers (J 6 85 and K 6 20). Because of the large value of the 127 I nuclear quadrupole hyperfine constant, a significant portion of these assignments concerns clusters of hyperfine subcomponents, which are easily observable at 11 lm. These infrared data were combined in a least squares fit together with the existing microwave data on rotational transitions within the v 6 = 1 and v 3 = 2 vibrational states to get the upper state rotational constants and interacting parameters for the v 6 = 1 and v 3 = 2 states. Due to the high values of quantum numbers achieved during this infrared analysis, the final energy level calculation accounts for aC x ðD' ¼ AE1; DK ¼ AE1Þ and an a ðD' ¼ Ç1; DK ¼ AE2Þ types of Coriolis interactions coupling the v 6 = 1 energy levels with those from the v 3 = 2 and v 2 = 1 states, respectively. On the other hand, it proved unnecessary to update the existing hyperfine parameters for the v 6 = 1 and v 3 = 2 states.

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“…To the best of our knowledge, only four studies dealt with the measurement of line broadening coefficients. Self-broadening parameters of 6 hyperfine components of the ( J = 10 → 9, K l = 9) rotational transitions in the v 6 = 1 excited vibrational state were accurately measured using Doppler-free double-resonance spectroscopy [8] and room temperature self-, N 2 -and O 2 -broadening coefficients were measured for over 100 lines in five Q -branches of the ν 5 perpendicular band at 7 μm using diode laser absorption spectroscopy [9] . More recently, Raddaoui et al [10] used high resolution Fourier transform spectra and a multispectrum fitting procedure with Voigt profile to retrieve self-broadening coefficients for around 1200 transitions of the ν 6 band between 854 and 963 cm -1 .…”

Section: Introductionmentioning

confidence: 99%

Oxygen broadening and shift coefficients in the ν6 band of methyl iodide (12CH3I) at room temperature

Attafi

Galalou

Tchana

et al. 2019

Journal of Quantitative Spectroscopy and Radiative Transfer

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In this study we report the high-resolution measurements of oxygen pressure-broadening and pressureinduced shift coefficients for rovibrational transitions in the ν 6 band of methyl iodide (12 CH 3 I), centered at 892.918 cm-1. The results were obtained by analyzing fourteen high-resolution room temperature laboratory absorption spectra with a mono-spectrum non-linear least squares fitting of Voigt profiles. The data were recorded with the Bruker IF125HR Fourier transform spectrometer located at the LISA facility in Créteil, using a White type cell with a path length of 564.9 cm and total pressures up to 295 hPa. The measured oxygen-broadening coefficients range from 0.0648 to 0.1207 cm-1 atm-1 at 295 K. The measured shift coefficients were all negative and varied between −0.0 0 044 and −0.04984 cm-1 atm-1. The average accuracy on the measured O 2-broadening coefficients and pressure shift coefficients was estimated to about 4% and 11%, respectively. The O 2-broadening coefficients obtained in the present work are compared with values reported in the literature for the ν 5 band of CH 3 I, showing a satisfactory agreement with an average difference of about 8%. The shift coefficients are compared with values reported in the literature for the ν 6 band of CH 3 FAr system, exhibiting the same order of magnitude and trend. The J and K rotational dependences of the O 2-broadening coefficients have been observed and the latter modeled using empirical polynomial expansions. On average, the empirical expression reproduces the measured O 2-broadening coefficients to within 3%. Using the measured broadening coefficients of the CH 3 I-O 2 and CH 3 IN 2 [Attafi et al., J Quant Spectrosc Radiat Transf 231 (2019) 1-8] systems, we produced CH 3 I-air broadening coefficients, ranging from 0.0783 to 0.1385 cm-1 atm-1 at 295 K. The present results and the data already available should be valuable not only for predicting the CH 3 I infrared spectrum in the atmosphere, but also for verifying theoretical calculations of pressure-broadening and pressure-shift coefficients in the ν 6 region of methyl iodide spectra.

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Hyperfine Level Dependence of the Pressure Broadening of CH3I Rotational Transitions in the v6 = 1 Vibrational State

Cited by 18 publications

References 19 publications

Self and N2 collisional broadening of rovibrational lines in the ν6 band of methyl iodide (12CH3I) at room temperature: The J and K dependence

Self and N2 collisional broadening of rovibrational lines in the ν6 band of methyl iodide (12CH3I) at room temperature: The J and K dependence

New analysis of the ν6 and 2ν3 bands of methyl iodide (CH3I)

Oxygen broadening and shift coefficients in the ν6 band of methyl iodide (12CH3I) at room temperature

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