Measurements of linestrengths, N2-, Ar-, He- and self-broadening coefficients of acetylene in the ν4+ν5 combination band using a cw quantum cascade laser

Abstract

Measurements of linestrengths, N2-, Ar-, He-and selfbroadening coefficients of acetylene in the 4+5 combination band using a cw quantum cascade laser KAUST Repository AbstractLinestrengths, N 2 -, Ar-, He-and self-broadening coefficients of acetylene have been measured at 296 K in the P branch of the ν 4 +ν 5 combination band for 25 rotational transitions. The effect of gas temperature is studied over 296 -683 K for five transitions to allow the determination of the temperature dependent exponent n for N 2 -and Ar-broadening coefficients. These measurements were performed using a continuous-wave quantum cascade laser (cw-QCL) operating over 1253 -1310 cm -1 . Spectroscopic parameters were obtained by fitting absorption spectra using Voigt, Galatry and Rautian profiles. Linestrength and broadening results are compared with previous studies available in literature for the ν 4 +ν 5 combination band and other vibrational bands of acetylene.

O2-broadening coefficients of acetylene lines in the ν4+ν5 band at room temperature

“…Dicke narrowing and speed dependence). This behavior was also observed in many other studies of the line shape of C 2 H 2 [35,[37][38][39][40][41]. The results of O 2 -broadening coefficients of the C 2 H 2 transitions considered in this work, obtained using the Voigt profile as well as the RP, GP and qSDVP are then compared with previous studies, realized for other bands in Fig.…”

“…While a large number of studies devoted to the determination of spectroscopic parameters of C 2 H 2 used the VP, RP and GP [34][35][36][37][38][39][40][41], the SDVP was recently used to test the speed dependence effect on the collisional broadening and shifting parameters of acetylene lines [53][54][55]. In Refs.…”

“…The strengths and self-broadening coefficients of the transitions of this band were measured at room temperature [34,35]. Other studies were performed to obtain N 2 -, Ar-, He-, CO 2 -, and Xe-broadening coefficients at various temperatures [36][37][38][39][40][41]. To the best of our knowledge, no O 2 -broadening coefficients of C 2 H 2 in the m 4 + m 5 band have been reported yet.…”

Intensities, broadening and narrowing parameters in the ν 3 band of methane

“…Data analysis was carried out following the fitting procedure used previously to determine the spectroscopic parameters of ammonia [50] and acetylene [51]. The line intensities and broadening coefficients were derived from Voigt and Galatry profiles by fitting the absorption line shape measurements at various pressures.…”

High-temperature measurements of methane and acetylene using quantum cascade laser absorption near 8 μm

“…The spectroscopic region near 8 μm has been investigated in several studies to determine linestrengths, self-and foreign-gas broadening coefficients and their temperature dependent exponents for the ν 4 band of methane [39][40][41][42] and the ν 4 þν 5 band of acetylene [43][44][45][46][47][48][49]. Most of these studies were performed near or below room temperature with relevance to atmospheric and astrophysical applications.…”