| 1. |
- Afzelius, Mikael, et al.
(författare)
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Exact treatment of classical trajectories governed by an isotropic potential for linewidth computations
- 2004
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Ingår i: Molecular Physics. - : Informa UK Limited. - 1362-3028 .- 0026-8976. ; 102:16-17, s. 1759-1765
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Tidskriftsartikel (refereegranskat)abstract
- Two models for exact classical trajectories in the field of an isotropic potential are investigated for the purpose of semiclassical linebroadening calculations. The first directly uses the exact solution of the classical equation of motion. The second starts from the equation of motion and computes the trajectory by numerical solution of the differential equations. In the framework of both models, all the computations are performed numerically, thus allowing the use of refined ab initio potential energy surfaces. For the example of the linebroadening of pure nitrogen and carbon monoxide, it is shown that, owing to the dominant short-range forces in these self-perturbed molecular systems, the limiting case corresponding to traditional parabolic trajectories can be used without any important loss of precision.
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| 2. |
- Buldyreva, J, et al.
(författare)
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Linewidth modelling of C2H2-N-2 mixtures tested by rotational CARS measurements
- 2006
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Ingår i: Journal of Raman Spectroscopy. - : Wiley. - 1097-4555 .- 0377-0486. ; 37:6, s. 647-654
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Tidskriftsartikel (refereegranskat)abstract
- The acetylene-nitrogen system is investigated in a combined theoretical and experimental effort in view of its thermometry applications. Accurate values of the rotational Raman linewidths of acetylene are of crucial importance for the computation of spectra from rotational coherent anti-Stokes Raman scattering (CARS) used for temperature and concentration evaluations. Since the direct measurements of these linewidths are not available, they are rigorously calculated by a semi-classical Robert-Bonamy formalism employing exact trajectories. The computed linewidths are used as input parameters in the theoretical spectra simulation, which is also improved by the inclusion of an interbranch interference with coherent Stokes Raman scattering (CSRS). These theoretical spectra are used to evaluate the temperature from experimental CARS spectra of acetylene-nitrogen mixtures recorded in the pressure range 0.1-0.6 MPa. The new linewidths (NLWs) and the CSRS interference inclusion result in a clear improvement of spectral fitting as well as in reasonable values of evaluated temperatures. Copyright (c) 2006 John Wiley & Sons, Ltd.
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