Recommended isolated-line profile for representing high-resolution spectroscopic transitions (IUPAC Technical Report)

The report of an IUPAC Task Group, formed in 2011 on "Intensities and line shapes in high-resolution spectra of water isotopologues from experiment and theory" (Project No. 2011-022-2-100), on line profiles of isolated high-resolution rotational-vibrational transitions perturbed by neutral gas-phase molecules is presented. The well-documented inadequacies of the Voigt profile (VP), used almost universally by databases and radiative-transfer codes, to represent pressure effects and Doppler broadening in isolated vibrational-rotational and pure rotational transitions of the water molecule have resulted in the development of a variety of alternative line-profile models. These models capture more of the physics of the influence of pressure on line shapes but, in general, at the price of greater complexity. The Task Group recommends that the partially Correlated quadratic-Speed-Dependent Hard-Collision profile should be adopted as the appropriate model for high-resolution spectroscopy. For simplicity this should be called the Hartmann--Tran profile (HTP). The HTP is sophisticated enough to capture the various collisional contributions to the isolated line shape, can be computed in a straightforward and rapid manner, and reduces to simpler profiles, including the Voigt profile, under certain simplifying assumptions.Comment: Accepted for publication in Pure and Applied Chemistr

CH3CN self-broadening coefficients and their temperature dependences for the Earth and Titan atmospheres

Theoretical self-broadening coefficients and associated temperature dependences for methyl cyanide lines in parallel (ΔK = 0) bands are reported for large ranges of rotational quantum numbers (0 ⩽ J ⩽ 70, K ⩽ 20) requested by spectroscopic databases. The calculations are performed by a semi-empirical method, particularly suitable for active molecules with large dipole moments, which needs only a few experimental data for model parameters fitting. Since the common power law for the temperature-dependence exponents is invalid for wide temperature ranges, two separate sets of temperature exponents are provided for Earth and Titan atmospheres applications

Linewidths and temperature exponents of CH3CN-N2

Calculations of nitrogen-broadening coefficients and their temperature exponents for methyl cyanide lines at the room temperature using semi-empirical method are presented. They were performed for wide ranges of rotational quantum numbers J and K requested for atmospheric applications: J from 0 till 70 and K from 0 till 20. The temperature exponents were calculated for every mentioned line. Extensive line lists are provided for the Earth and Titan atmosphere temperature ranges. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

N2-broadening coefficients of CH3CN rovibrational lines and their temperature dependence for the Earth and Titan atmospheres

International audienc

Evidence of stable van der Waals CO2 clusters relevant to Venus atmosphere conditions

International audienc

Non-Markovian rotational relaxation matrix for fast collisions between two linear molecules in high-pressure gaseous media. I. General formalism and preliminary testing

International audienc