ABSTRACT
In this paper, we present the different theoretical line profiles, which can be used to describe a shape of molecular transitions in dilute gases: the Voigt, Galatry, Rautian and speed dependence models. We discuss their limitations and their advantages, and present for illustration different comparisons of model results with experimental data obtained with several diode laser spectrometers suitable for precise line shape measurements.
Subject(s)
Chemistry Techniques, Analytical/instrumentation , Lasers , Chemistry Techniques, Analytical/methods , Data Interpretation, Statistical , Spectrum Analysis/instrumentation , Spectrum Analysis/methods , TemperatureABSTRACT
The pressure-induced Xe shifting and broadening coefficients for five lines of 12CH(3)D in the nu(3) band near 7.5 microm have been measured using a tunable diode-laser spectrometer. The frequency shift was determined from the simultaneous record of the Xe-broadened line and the same line of pure CH(3)D at low pressure. Comparisons are made with the results of theoretical calculations based on a semiclassical model involving the atom-atom Lennard-Jones (LJ) potential.
Subject(s)
Deuterium/chemistry , Methane/chemistry , Xenon/chemistry , Lasers , Spectrum AnalysisABSTRACT
Absolute intensities have been measured for 26 lines of C2H4 in the nu7 fundamental transition, using a tunable diode-laser spectrometer. These lines with 3< or = J"< or = 21, 2< or = Ka< or = 4, 2< or = Kc< or = 20 are located in the spectral range 920-980 cm(-1). The intensities have been measured by using two methods: the equivalent width method (EWM) and the line profile fit method (FPM). For the last one, three models have been tested: Voigt, Rautian and Galatry profiles.
Subject(s)
Ethylenes/chemistry , Lasers , Spectrophotometry, Infrared/methods , Spectrophotometry, Infrared/statistics & numerical dataABSTRACT
This work presents a synthesis of our results concerning line intensities and self-broadening coefficients for ClCN in the diad (nu1, 2nu 2 0). Absolute band strengths have been determined. The influence of the perturbation in these band strengths due to a Fermi resonance between the 10(0)0 and 02(0)0 levels has been analyzed.
Subject(s)
Cyanides/chemistry , Lasers , Spectrophotometry, Infrared/methodsABSTRACT
Using a stabilized diode-laser spectrometer, we have studied the line profiles of water vapor near 7185.59 cm(-1). With low pressures of pure gas (
ABSTRACT
With a tunable diode-laser spectrometer, absolute line intensity measurements have been made in the spectrum of cyanogen chloride in the vicinity of 710 cm(-1). The intensity of the fundamental nu(1) band has been found to be 6.088 cm(-2) atm(-1) for the (35)ClCN isotopomer and 7.121 cm(-2) atm(-1) for the (37)ClCN form. The influence of the Fermi resonance on the band intensity has been analyzed. Copyright 2001 Academic Press.
ABSTRACT
The self-broadening coefficients and the intensities of 29 lines in the nu(1) band of cyanogen chloride ((35)Cl(12)C(14)N) have been measured at high resolution in the range 699-736 cm(-1), using a tunable diode-laser spectrometer. The collisional widths and most of the intensities are obtained by fitting Voigt and Rautian profiles to the measured shapes of the lines. From the analysis of the line intensities we determine the absolute strength as well as the Herman-Wallis factors for the nu(1) band. A semiclassical calculation of the self-broadening coefficients, performed by considering the main electrostatic interactions only, has provided larger results than the experimental data. Copyright 2001 Academic Press.
