On far‐wing Raman profiles by CO₂

Abstract

The anisotropic scattering spectrum of the symmetric stretching n 1 band by CO 2 was recorded up to the far Stokes wing, and its theoretical analysis was attempted through the non-Markovian energy-corrected sudden approximation -a useful approach which has thus far been successfully applied to the anisotropic scattering spectrum by N 2 , up to the far wing. Despite the excellent agreement observed in N 2 here, a substantial inconsistency between theory and experiment was found in the wing of the spectrum. Although the influence of other missing processes or neighboring bands cannot be totally excluded, our findings rather suggest that highly anisotropic perturbers, such as CO 2 , are improperly described when they are handled as point-like molecules, a cornerstone hypothesis in the approach employed.

Pressure effects on N2–N2 rototranslational Raman spectra predicted from leading spectral moments

“…The non-Markovian ECS-BC method (assuming a structureless bath) works well for the N 2 -N 2 system because of the nearly isotropic interaction between two small N 2 molecules. In the case of longer and more anisotropic colliders like CO 2 , it gives underestimated intensities in the far wing, [18] so that the internal structure of the perturber should be accounted for, as it is done in the present spectral-moments approach.…”

Depolarisation of rotational orientation and alignment of OH (X2Π) in collisions with molecular partners: N2 and O2

“…57,58 These studies indicate that there is a considerably deeper attractive minimum at short range in the OH(X)-O 2 potential than for OH(X)-N 2 . On the other hand, a number of related collisional experiments 19,[34][35][36][37]59,60 suggest larger cross-sections for N 2 than O 2 , which have conventionally been explained by stronger long-range interactions due to the larger N 2 quadrupole moment. We discover here which of these opposing factors might dominate in the combination of inelastic and elastic depolarisation processes sampled by the PS method.…”

Advances in nonlinear optical spectroscopies: a historical perspective of developments and applications presented at ECONOS

“…A small number of spontaneous Raman scattering studies have therefore been included in the special issues. Chrysos et al published a series of papers on collisioninduced scattering spectroscopy of carbon dioxide, [130,131] nitrogen, [130] and noble gases such as neon [132,133] and argon. [131,133,134] Schlüter et al demonstrated the application of a Raman gas analyzer for anesthesia monitoring.…”