2-7 June 2019
Simon Fraser University
America/Vancouver timezone
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Do the temperature dependencies of spectral line parameters change when we approach cryogenic temperatures?

3 Jun 2019, 14:15
15m
BLU 10011 (Simon Fraser University)

BLU 10011

Simon Fraser University

Oral (Non-Student) / Orale (non-étudiant(e)) Division of Atomic, Molecular and Optical Physics, Canada / Division de la physique atomique, moléculaire et photonique, Canada (DAMOPC-DPAMPC) M2-1 Interaction Between Matter and Light (DAMOPC) | Interaction de la matière et de la lumière (DPAMPC)

Speaker

Adriana Predoi-Cross (University of Lethbridge)

Description

We have recently studied a set of 40 spectra of carbon monoxide in pure state and mixed with air, recorded at temperatures between 79 to 296 K. Our aim was to investigate if the temperature dependencies of line parameters, such as half widths and pressure induced shifts, stay the same at very low temperatures, close to 79 K. The spectra were all recorded over two decades using the 1-m Fourier Transform spectrometer located at Kitt Peak, AZ, USA and two temperature controlled gas cells. The spectra were calibrated using the line positions for residual carbon dioxide and water vapour and referencing them to the HITRAN database.
The constrained analysis technique was used together with the software Labfit [2]. Three line shape models were employed: Voigt, speed-dependent Voigt and Rautian. In the absence of experimental narrowing parameters, we have calculated them using computed diffusion constants [3].
The theoretical half-width coefficients for CO-N2 have been determined at several temperatures employing a potential energy surface of Tipping-Herman type, vibrationally independent potentials and by taking into account the electrostatic interactions. We will discuss what laws were fund to best represent the temperature dependencies over a wide range of temperatures, approaching cryogenic temperatures.
We thank D. Chris Benner for the Labfit software. The work of V.M. Devi was funded by NASA grants and contracts, and the research by M. A. H. Smith was performed as part of her employment at NASA Langley Research Center. No official endorsements are intended or implied. N. Islam and A. Predoi-Cross have been funded by NSERC. S. Ivanov and O. Byzykin received financial support from the Ministry of Science and Higher Education within the State assignment FSRC «Crystallography and Photonics» RAS and Russian Science Foundation (Project No.18-55-16006).

References:
1. I.E. Gordon, L.S. Rothman, C. Hill, R.V. Kochanov, Y. Tan, P.F. Bernath, et al. J. Quant. Spectrosc. Radiat. Transfer 203, 3–69 (2017).
2. D.C. Benner, C.P. Rinsland, V.M. Devi, M.A.H. Smith, D. Atkins, J. Quant. Spectrosc. Radiat. Transfer 53(6), 705-721 (1995).
3. J.O. Hirschfelder, C.F. Curtiss, R.B. Bird, Molecular theory of gases and liquids. New York: Wiley and Sons, 1952.

Primary authors

Adriana Predoi-Cross (University of Lethbridge) Mr Nazrul Islam (University of Lethbridge) Dr Mary Ann Smith (Science Directorate, NASA Langley Research Center) Dr Malathy Devi (Department of Physics, The College of William and Mary) Dr Sergey Ivanov (Institute on Laser and Information Technologies, Russian Academy of Sciences) Dr Oleg Buzykin (Central Aerohydrodynamic Institute (TsAGI)) Prof. Franck Thibault (Universite de Rennes)

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