Rovibrational spectrum and potential energy surface of the N2-N2O van der Waals complex

The rovibrational spectrum of the N-2-N2O van der Waals complex has been recorded in the N2O nu(1) region (similar to 1285 cm(-1)) using a tunable diode laser spectrometer to probe a pulsed supersonic slit jet. The observed transitions together with the data observed previously in the N2O nu(3) region are analyzed using a Watson S-reduced asymmetric rotor Hamiltonian. The rotational and centrifugal distortion constants for the ground and excited vibrational states are accurately determined. The band-origin of the spectrum is determined to be 1285.73964(14) cm(-1). A restricted two-dimensional intermolecular potential energy surface for a planar structure of N-2-N2O has been calculated at the CCSD(T) level of theory with the aug-cc-pVDZ basis sets and a set of mid-bond functions. With the intermolecular distance fixed at the ground state value R = 3.6926 angstrom, the potential has a global minimum with a well depth of 326.64 cm(-1) at 0(N2) = 11.0 degrees and 0(N2O) = 84.3 degrees and has a saddle point with a barrier height of 204.61 cm(-1) at 0(N2) = 97.4 degrees and 0(N2O) = 92.2 degrees, where 0(N2) (0(N2O)) is the enclosed angle between the N-N axis (N-N-O axis) and the intermolecular axis. (c) 2011 Elsevier Inc. All rights reserved.