ANALYSIS OF SELF-BROADENED SPECTRA IN THE $\nu_{5}$ AND $\nu_{6}$ FUNDAMENTAL BANDS OF $^{12}CH_{3}D$

Loading...
Thumbnail Image

Date

2000

Journal Title

Journal ISSN

Volume Title

Publisher

Ohio State University

Research Projects

Organizational Units

Journal Issue

Abstract

A multispectrum nonlinear least-squares fitting $technique^{a}$ has been applied to determine accurate line center positions, absolute line intensities, Lorentz self-broadening coefficients and self-induced pressure-shift coefficients for a large number of transitions in the two perpendicular fundamental bands of $^{12}CH_{3}D$ near 1160 and $1470 cm^{-1}$. We analyzed together high-resolution room temperature absorption spectra recorded with two Fourier transform spectrometers (FTS). Three spectra were recorded using the Bruker IFS 120 HR at PNNL at $0.002 cm^{-1}$ resolution, and fourteen spectra were obtained with the McMath-Pierce FTS $(0.006 cm^{-1}$ resolution) at the National Solar Observatory on Kitt Peak. Self-broadening coefficients for over 1000 transitions and self-shift coefficients for more than 800 transitions were determined. The measurements include transitions with rotational quantum numbers over $J^{\prime\prime} = 15$ and $K^{\prime\prime} = 15$ and some forbidden transitions. Measurements were made in all sub-bands $(^{P}P, ^{P}Q, ^{P}R, ^{R}P, ^{R}Q$ and $^{R}R$). The measured broadening coefficients vary from 0.040 to $0.096 cm^{-1}$ at $m^{-1}$ 296K. Self-shift coefficients vary from about -0.014 to $+0.004 cm^{-1} atm^{-1}$. Less than 5% of the measured shift coefficients are positive, and majority of these positive shifts are associated with the $J^{\prime\prime} = K^{\prime\prime}$ transitions in the $^{P}Q$ sub-bands. The values for the two perpendicular bands are compared and discussed.

Description

Author Institution: Jet Propulsion Laboratory, California Institute of Technology; Department of Physics, The College of William and Mary; Atmospheric Sciences, NASA Langley Research Center. Mail Stop 401A; Atmospheric Sciences, Pacific Northwest National Laboratory (PNNL)

Keywords

Citation