The v4=1 State of 14NF3 at 493 cm−1 Studied by High-Resolution FTIR, Centimeter-Wave, and Millimeter-Wave Spectroscopy

✍ Scribed by N. Boulaftali; N.Ben Sari-Zizi; U. Wötzel; J. Demaison; L. Margulès; H. Harder; H. Mäder; E.B. MKadmi; H. Bürger

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 251 KB
• Volume: 212
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.2001.8505

✦ Synopsis

The ν 4 band of NF 3 , ν0 = 493.423 cm -1 , has been studied by FTIR spectroscopy with a resolution of 3 × 10 -3 cm -1 . Strong intensity perturbation by (2, 2) resonance is revealed. The more than 5000 IR assignments were complemented by 132 millimeter-wave measurements in the regions 140-250 and 340-470 GHz, by 7 new or formerly reported J = 1-0 and 3-2 microwave frequencies, and by 134 J = 0, k = = ±2 direct -type centimeter-wave transitions in the region 8-26 GHz with J max = 22 and (k -) max = 15. The rotational data enabled detection of splittings caused by (2, -4) (t) and (0, 6) (h 3 ) interactions in excess to those by (2, 2) (q) effects. The A 1 A 2 splitting of the k = -2 level was not detected on the K = -1 IR transitions owing to their vanishing intensity for J > 18. In contrast, A 1 A 2 doublets were observed in transitions with 28 ≤ J ≤ 43 reaching the k = +4 level. All appropriately weighted observations were fitted together to 28 free parameters up to sextic terms employing three different (D, Q, Q D) reductions of the rovibrational Hamiltonian, and the equivalence of the reductions was established. The sets of molecular constants obtained from the merged data reproduce the IR observations with σ = 0.24 × 10 -3 cm -1 , the millimeter-wave data with σ = 29 kHz, and the centimeter-wave measurements with σ = 3 kHz.