Rotational study of the NH3-CO complex: Millimeter-wave measurements and ab initio calculations
| Autor: | L. A. Surin, A. Potapov, A. A. Dolgov, I. V. Tarabukin, V. A. Panfilov, S. Schlemmer, Y. N. Kalugina, A. Faure, A. van der Avoird |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Journal of Chemical Physics, 142, 114308 Journal of Chemical Physics, 142, 11, pp. 114308 Journal of chemical physics. 2015. Vol. 142, № 11. P. 114308-1-114308-10 |
| ISSN: | 0021-9606 |
| Popis: | The rotational spectrum of the van der Waals complex NH3-CO has been measured with the intracavity OROTRON jet spectrometer in the frequency range of 112-139 GHz. Newly observed and assigned transitions belong to the K = 0-0, K = 1-1, K = 1-0, and K = 2-1 subbands correlating with the rotationless (jk)NH3 = 00 ground state of free ortho-NH3 and the K = 0-1 and K = 2-1 subbands correlating with the (jk)NH3 = 11 ground state of free para-NH3. The (approximate) quantum number K is the projection of the total angular momentum J on the intermolecular axis. Some of these transitions are continuations to higher J values of transition series observed previously [C. Xia et al., Mol. Phys. 99, 643 (2001)], the other transitions constitute newly detected subbands. The new data were analyzed together with the known millimeter-wave and microwave transitions in order to determine the molecular parameters of the ortho-NH3-CO and para-NH3-CO complexes. Accompanying ab initio calculations of the intermolecular potential energy surface (PES) of NH3-CO has been carried out at the explicitly correlated coupled cluster level of theory with single, double, and perturbative triple excitations and an augmented correlation-consistent triple zeta basis set. The global minimum of the five-dimensional PES corresponds to an approximately T-shaped structure with the N atom closest to the CO subunit and binding energy De = 359.21 cm(-1). The bound rovibrational levels of the NH3-CO complex were calculated for total angular momentum J = 0-6 on this intermolecular potential surface and compared with the experimental results. The calculated dissociation energies D0 are 210.43 and 218.66 cm(-1) for ortho-NH3-CO and para-NH3-CO, respectively. |
| Databáze: | OpenAIRE |
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