Abstract

Room temperature argon broadened halfwidth and pressure-induced line shift coefficients have been determined for 118 transitions in the ν₄ band of ¹²CH₄ from analysis of high resolution laboratory absorption spectra recorded with the McMath Fourier transform spectrometer operated on Kitt Peak by the National Solar Observatory. Transitions up to J″ = 12 have been measured using a nonlinear least-squares spectral fitting procedure. The variation of the measured halfwidth coefficients with symmetry type and rotational quantum number is very similar to that measured previously for N₂ and air broadening, but the absolute values of the argon broadening coefficients are all smaller. On average, the ratio of the argon broadened halfwidth coefficient to the corresponding N₂ broadened halfwidth coefficient is 0.877 ± 0.017 (2σ). More than 95% of the pressure-induced shifts are negative with values ranging from −0.0081 to +0.0055 cm⁻¹ atm⁻¹. The pressure shifts in argon are nearly equal to corresponding values measured previously in N₂ and air.

© 1989 Optical Society of America

Measurements of air-broadened and nitrogen-broadened Lorentz width coefficients and pressure shift coefficients in the ν₄ and ν₂ bands of 12CH₄

Curtis P. Rinsland, V. Malathy Devi, Mary Ann H. Smith, and D. Chris Benner
Appl. Opt. 27(3) 631-651 (1988)

Air-broadened Lorentz halfwidths and pressure-induced line shifts in the ν₄ band of ¹³CH₄

V. Malathy Devi, Curtis P. Rinsland, Mary Ann H. Smith, and D. Chris Benner
Appl. Opt. 27(11) 2296-2308 (1988)

Measurements of air-, N₂-, and O₂-broadened halfwidths and pressure-induced line shifts in the ν₃ band of ¹³CH₄

V. Malathy Devi, D. Chris Benner, Mary Ann H. Smith, and Curtis P. Rinsland
Appl. Opt. 30(3) 287-304 (1991)

Absolute intensities and self-, N₂-, and air-broadened Lorentz halfwidths for selected lines in the ν₃ band of ¹²CH₃D from measurements with a tunable diode laser spectrometer

V. Malathy Devi, Curtis P. Rinsland, D. Chris Benner, Mary Ann H. Smith, and K. B. Thakur
Appl. Opt. 25(11) 1848-1853 (1986)

Linewidth measurements in the thermal infrared bands of ¹²CH₃D at planetary atmospheric temperatures

Prasad Varanasi and S. Chudamani
Appl. Opt. 28(11) 2119-2122 (1989)