A new study of the ν 2(A 1) infrared band of phosphorus trifluoride

Abstract

The high-resolution Fourier transform infrared spectrum of phosphorus trifluoride (PF3) has been reinvestigated in the v2 = 1 vibrational excited state near 487 cm−1 (at a resolution of 3 × 10–3 cm–1). Thanks to our new accurate rotational ground-state C 0 value, 0.159970436(69) cm–1, and to recent pure rotational measurements, 318 new infrared transitions of the ν 2 fundamental band have been assigned, extending the rotational quantum number values up to K max = 71 and J max = 72. A merge, for the first time, of 135 reported microwave data (K max = 42 and J max = 49) within the v2 = 1 excited level and 2860 rovibrational transitions yielded improved constants of ν 2. Parameters of this band have been obtained, up to sextic centrifugal distortion constants, by least-squares fits, σ IR = 3.60 × 10–4 cm–1 and σ MW = 5.53 × 10–6 cm–1 (166 kHz). Comparison of these constants with those measured previously by infrared spectroscopy reveals orders of magnitude higher accuracy of these new values.