Eur. Phys. J. D (2012) 66: 228
https://doi.org/10.1140/epjd/e2012-20758-4

Regular Article

Spectroscopic study of self and buffer gas broadened CO₂ overtone transitions at 780 nm by NIR diode laser spectrometer

Department of Physics, University of Calcutta, 92 A. P. C. Road, 700009 Kolkata, India

^a e-mail: brphy@caluniv.ac.in

Received: 26 December 2011
Received in final form: 18 May 2012
Published online: 4 September 2012

Abstract

A high resolution near infrared (NIR) diode laser spectrometer along with a multipass cell is used to detect weak rovibronic transitions of carbon dioxide in the NIR region. The self, nitrogen and air broadening line shape parameters of three rovibrational transitions P(44), P(46) and P(48) of ¹²C¹⁶O₂ belonging to the (ν₁ + 5   ν₃) overtone band around 780 nm are studied. Wavelength modulation spectroscopy with phase sensitive detection technique at the first harmonic is used to detect the weak overtone transitions of CO₂. The observed line shapes are fitted with the standard Voigt profile by a non-linear least squares fitting program in order to determine the self and buffer gas (air and N₂) broadening coefficients and line strength parameters of the CO₂ transitions. The O₂ broadening coefficients are calculated from the experimentally measured N₂ and air broadening coefficient values. The measured parameters are compared with the available experimental data and a reasonable agreement has been found.