On the isotropic Raman spectrum of Ar{sub 2} and how to benchmark ab initio calculations of small atomic clusters: Paradox lost

Journal Article · Tue Jul 14 04:00:00 EDT 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4923370· OSTI ID:22490895

Chrysos, Michael; Rachet, Florent ^[1]; Dixneuf, Sophie ^[2]

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1. LUNAM Université, Université d’Angers, CNRS UMR 6200, Laboratoire MOLTECH-Anjou, 2 Bd Lavoisier, 49045 Angers (France)
2. Centre du Commissariat à l’Énergie Atomique de Grenoble, Laboratoire CEA-bioMérieux, Bât 40.20, 17 rue des Martyrs, 38054 Grenoble (France)

This is the long-overdue answer to the discrepancies observed between theory and experiment in Ar{sub 2} regarding both the isotropic Raman spectrum and the second refractivity virial coefficient, B{sub R} [Gaye et al., Phys. Rev. A 55, 3484 (1997)]. At the origin of this progress is the advent (posterior to 1997) of advanced computational methods for weakly interconnected neutral species at close separations. Here, we report agreement between the previously taken Raman measurements and quantum lineshapes now computed with the employ of large-scale CCSD or smartly constructed MP2 induced-polarizability data. By using these measurements as a benchmark tool, we assess the degree of performance of various other ab initio computed data for the mean polarizability α, and we show that an excellent agreement with the most recently measured value of B{sub R} is reached. We propose an even more refined model for α, which is solution of the inverse-scattering problem and whose lineshape matches exactly the measured spectrum over the entire frequency-shift range probed.

• OSTI ID: 22490895
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 2 Vol. 143; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ATOMIC CLUSTERS
COMPUTER CALCULATIONS
COMPUTERIZED SIMULATION
EVALUATION
POLARIZABILITY
RAMAN SPECTRA