期刊
JOURNAL OF CHEMICAL PHYSICS
卷 141, 期 10, 页码 -出版社
AIP Publishing
DOI: 10.1063/1.4894419
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资金
- Groupement de Recherche International SAMIA
- IDRIS computer centre of CNRS France
- Centre Informatique National de l'Enseignement Superieur (CINES) computer centre
- computer centre Reims-Champagne-Ardenne
- Tomsk State University Competitiveness Improvement Program
In this paper we report a new ground state potential energy surface for ethylene (ethene) C2H4 obtained from extended ab initio calculations. The coupled-cluster approach with the perturbative inclusion of the connected triple excitations CCSD(T) and correlation consistent polarized valence basis set cc-pVQZ was employed for computations of electronic ground state energies. The fit of the surface included 82 542 nuclear configurations using sixth order expansion in curvilinear symmetry-adapted coordinates involving 2236 parameters. A good convergence for variationally computed vibrational levels of the C2H4 molecule was obtained with a RMS(Obs.-Calc.) deviation of 2.7 cm(-1) for fundamental bands centers and 5.9 cm(-1) for vibrational bands up to 7800 cm(-1). Large scale vibrational and rotational calculations for (C2H4)-C-12, (C2H4)-C-13, and (C2D4)-C-12 isotopologues were performed using this new surface. Energy levels for J = 20 up to 6000 cm(-1) are in a good agreement with observations. This represents a considerable improvement with respect to available global predictions of vibrational levels of (C2H4)-C-13 and (C2D4)-C-12 and rovibrational levels of (C2H4)-C-12. (C) 2014 AIP Publishing LLC.
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