Explicitly correlated potential energy surface of the CH3Cl–He van der Waals complex and applications
| Autor: | Majdi Hochlaf, H. Aroui, A. Ben Krid, Y. Ajili, M. Dhib, D. Ben Abdallah |
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| Rok vydání: | 2021 |
| Předmět: |
Physics
010304 chemical physics Jacobi coordinates Ab initio General Physics and Astronomy Electronic structure 010402 general chemistry 01 natural sciences Molecular physics Spectral line 0104 chemical sciences symbols.namesake 0103 physical sciences Potential energy surface Physics::Atomic and Molecular Clusters symbols Center of mass Physics::Chemical Physics Physical and Theoretical Chemistry van der Waals force Basis set |
| Zdroj: | The Journal of Chemical Physics. 154:094304 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/5.0038677 |
| Popis: | A new 3D-potential energy surface (3D-PES) for the weakly bound CH3Cl-He complex is mapped in Jacobi coordinates. Electronic structure calculations are performed using the explicitly correlated coupled clusters with single, double, and perturbative triple excitations approach in conjunction with the aug-cc-pVTZ basis set. Then, an analytical expansion of this 3D-PES is derived. This PES shows three minimal structures for collinear C-Cl-He arrangements and for He located in between two H atoms, in the plane parallel to the three H atoms, which is near the center of mass of CH3Cl. The latter form corresponds to the global minimum. Two maxima are also found, which connect the minimal structures. We then evaluated the pressure broadening coefficients of the spectral lines of CH3Cl in a helium bath based on our ab initio potential. Satisfactory agreement with experiments was observed, confirming the good accuracy of our 3D-PES. We also derived the bound rovibronic levels for ortho- and para-CH3Cl-He dimers after quantum treatment of the nuclear motions. For both clusters, computations show that although the ground vibrational state is located well above the intramolecular isomerization barriers, the rovibronic levels may be associated with a specific minimal structure. This can be explained by vibrational localization and vibrational memory effects. |
| Databáze: | OpenAIRE |
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