E-catalog        

Библиогр.: 39 назв.

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.