Self- and Foreign-Gas-Broadening and Shifting of Lines in the ν2Band of HCN

Line Broadening and Mixing in NH3 Inversion Doublets Perturbed by NH3, He, Ar, and H2

“…Except at low J , the theoretical values are then notably greater than the experimental ones, especially for K approaching or equal to J , and the calculation strongly exaggerates the K dependence of the broadening. This overestimation is not surprising since it is generally observed for molecules with a large dipole and/or quadrupole moment such as CH 3 Cl (35), OCS (52), or HCN (53). Finally note that, for the studied lines, the ratio of H 2 to He broadening is practically constant and equal to 2.7, whereas γ Ar /γ He has a mean value of 1.55; in contrast, self-broadening has a very different behavior.…”

Infrared HCN Lineshapes as a Test of Galatry and Speed-Dependent Voigt Profiles

“…However, proposed interpretations differ according to the considered spectral domain. In the infrared range, line narrowings induced by Ar and N 2 in the ν 1 (30,31) and ν 2 (32,33) bands and in the ν 1 + ν 2 (34) combination band have been observed: they are claimed to be related to the Dicke effect. Extensive results have also been obtained by the coherent transient technique (optical precession) on centimeter (35) and millimeter (36) lines of HC 15 N in collision with a large variety of buffer gases: from ab initio calculations of collisional relaxation rates, it has been concluded that observed narrowings result mainly from the speed dependence of relaxation.…”

Diode-Laser Measurements of H2-Broadening Coefficients in the ν2Band of HCN

“…electrostatic interactions were not taken into account when para-H 2 (J 2 Å 0) was the collider. Indeed, because H 2 in the state J 2 Å 0 is spherically symmetrical, terms in the potential for ÉmÉ Å 1 to 0.992 for ÉmÉ Å 30) than those obtained which depend on the orientation of the H 2 molecule do not previously (4). As shown in Figs.…”

“…An lar to those described in detail respectively in Refs. (10,4) example of the spectra obtained for the R (16) line is shown and they are briefly presented in the following sections.…”