作者:Helen O. Leung
DOI:10.1063/1.478321
日期:1999.3.1
The rotational spectrum of 15N2–14N2O has been recorded in the 7–19 GHz region with a pulsedmolecular beam,Fourier transformmicrowavespectrometer. An internal motion of the 15N2 subunit has been observed and the nuclear quadrupole hyperfine structurein each internal motion state has been analyzed using the WatsonS-reduced Hamiltonian with the inclusion of nuclear quadrupole couplinginteractions. The spectroscopic constants of the ground internal motion state are not welldetermined since only 4 transitions have been observed, but they are similar to those ofthe excited internal motion state that are determined from the analysis of 14a- and b-type transitions. The rotational andcentrifugal distortion constants (in MHz) for the excited internal motion state areA=12 791.307 0(2),B=2 014.982 4(1),C=1 728.950 45(7),DJ=1.052 5(2)×10−2,DJK=3.933 7(3)×10−1,d1=−1.822(3)×10−3,d2=−1.118(6)×10−3. The nuclear quadrupole coupling constants (in MHz) in the excitedinternal motion state for the terminal 14N nucleus in N2O are χaa=0.3465(4),χbb=−0.7445(5), and χcc=0.3980(5), while those for the central 14N nucleus are χaa=0.1023(9),χbb=−0.2528(8), and χcc=0.1505(8). These spectroscopic constants are consistent with aT-shaped structure, with 15N2 forming the leg of the T. The intermolecular distance is3.691 Å. The 15N2 axis and the 14N2O axis make an angle of 13° and 81° with the intermolecularaxis, respectively. The nuclear quadrupole coupling constants show electric field gradient perturbationin the N2O subunit, with the field gradient at the central nitrogenaffected to a greater extent than that at the terminal nitrogen. This perturbation islikely due to electron charge redistribution in N2O upon complexation with N2.