Pulsed-beam Fourier transform microwave spectroscopy was used to measure a and b dipole transitions for the N2O-H35Cl, N 2O-H37Cl, N2O-D35Cl, and 15NNO-H35Cl van der Waals complexes. The observed transition frequencies were fit to determine the spectroscopic constants A-DK, B, C, Dj, DJK, eQqaa(Cl), and eQqbb(Cl). The structure of the complex appears to be a planar asymmetric top with a centers-of-mass separation Rc.m.- ≈ 3.51 Å. The angle θ between Rc.m. and the HCl axis is approximately 110°. The angle φ between the N2O axis and Rc.m. is approximately 77°. The structure was fit using a weighted least squares fit to B and C isotopic rotational constants with R c.m. θ, and φ as the adjustable parameters, and this procedure yielded three local minima with standard deviations less than 5 MHz. Principal axis coordinates for the Cl, H, and terminal N atoms in the complex were determined with single isotopic Kraitchman analysis to aid in the selection of the "best" structure. In a second structural analysis R c.m. θ, and φ values were determined from the spectroscopic constants B, C, and eQqaa(Cl). The "best fit" structure parameters for N2O-HCl are Rc.m. = 3.512(2) Å, θ = 110(9)°, and θ = 77(2)°. Ab initioa calculations of N2O-HCl structures using GAUSSIAN86 with MP2 yielded three energetically stable equilibrium conformations. One of the bound structures is very similar to the present experimental vibrationally averaged structure.
|Original language||English (US)|
|Number of pages||9|
|Journal||The Journal of Chemical Physics|
|Publication status||Published - 1991|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics