Infrared and microwave molecular-beam studies of N2O5

Rotational spectra of the P-r(0) and R-r(0) b-type subbands of N2O5 for both internal rotor states were recorded using a pulsed-nozzle Fourier-transform microwave spectrometer. The present measurements extend our previous results on N2O5 which were confined to the R-r(0), R-r(1), (r)Q(1), and P-r(1), b-type subbands due to limitations in the frequency coverage of the instrument. The present measurements provide new energy-level differences which give a nearly complete experimental picture of the K = 0, 1, and 2 energy levels. The measurements also support our previous picture of N2O5 as a C-2 symmetry molecule with facile geared internal rotation of the two equivalent NO2 groups. Infrared spectra of the 1246 cm(-1) nu(12), N-O stretching fundamental band of N2O5 were also recorded using a lead-salt diode-laser spectrometer and a slit-jet nozzle molecular-beam apparatus. The spectra reveal a complex resolved rotational structure which is at present unanalyzed. (C) 1997 Academic Press.