The combination bands (ν 1+ν 3, ν 2+ν 3) and overtone band (3ν 3) of neptunium hexafluoride

Abstract

Fourier transform, vibration-rotational spectra of NpF 6 measured at moderate to high resolution (0.1-0.008 cm −1) reveal well-defined PQR structures for the two combination bands, ν 1+ν 3 and ν 2+ν 3. The resolved ground-state Q branch and rotational manifolds for each band provide accurate vibrational frequencies and allow detailed rovibrational analysis. We also report the observation of the 3ν 3 band spectrum at 5.3 μm. The transition strength for 3ν 3 is determined as S=1.7×10 −2 km mol −1. The anharmonic constant x 33≈−0.77 cm −1 was estimated.