6533b826fe1ef96bd128459c

RESEARCH PRODUCT

Rotational collisional line broadening at high temperatures in the N2 fundamental Q-branch studied with stimulated Raman spectroscopy

subject

description

Self broadened N 2 Q-branch spectra are measured by high resolution stimulated Raman spectroscopy in the pressure region 0.25-1.9 atm. and in the temperature range 295-1310 K. Non additivity of the Q(J) components due to line overlap arising in the highest pressure range explored is carefully taken into account. Excellent fit of the whole spectra is thus obtained for each pressure with linearly density-dependent line widths. Semi-classical calculations of the line-broadening coefficients lead to consistent values with all the measured ones. These calculations are extended to higher J values and to higher temperatures (up to 2500 K). At last, a simple phenomenological model based on a polynomial inverse energy gap law for the rotational energy transfer rates is used to predict high temperature line widths. These predicted line widths are compared with those calculated a priori Etude a haute resolution pour des pressions de 0,25-1,9 atm. et des temperatures de 295-1310 K, en prenant en compte la non-additivite des composantes Q(J) due au recouvrement des raies pour les plus fortes pressions explorees. Calcul semi-classique des coefficients d'elargissement des raies pour des valeurs de J plus grandes et jusqu'a 2500 K. Utilisation d'un modele phenomenologique simple, base sur une loi polynomiale, en puissances inverses des ecarts d'energie, pour les taux de transfert d'energie rotationnelle a haute temperature