An investigation of the quadrupole coupling of two N nuclei in the complex pyrimidine-Ar by molecular beam Fourier transform microwave spectroscopy

The quadrupole coupling hyperfine structure of two equivalent N-14 nuclei in the rotational spectrum of pyrimidine-Ar complex has been investigated in the range of 6-18 GHz using molecular beam Fourier transform microwave spectroscopy. From the analysis of the hyperfine structure the elements chi(aa), chi(bb), chi(cc), and chi(bc), of the quadrupole coupling tensors in the principal inertial axis system of the complex have been determined. A comparison of the quadrupole constants of the complex with those of bare pyrimidine indicates that these constants are consistent with the structure of the complex previously reported, with the Ar atom tilted ca. 5degrees towards the two N atoms. This configuration is supported by ab initio calculations. (C) 2002 Elsevier Science B.V. All rights reserved.