High-Resolution Spectroscopic Measurements of the ν5 Bending Vibration–Rotation Band of HCCN in its X̃3Σ− State at 129 cm−1
✍ Scribed by Michael D. Allen; Kenneth M. Evenson; John M. Brown
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 666 KB
- Volume
- 209
- Category
- Article
- ISSN
- 0022-2852
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✦ Synopsis
The HCCN radical is known to be a quasi-linear molecule in its ground triplet state ( 3 -in the linear configuration). Vibration-rotation transitions in the HCC bending (ν 5 ) fundamental band have been detected around 129 cm -1 by the technique of far-infrared laser magnetic resonance (FIR LMR). Four FIR laser lines were used to record a total of 530 resonances. The observed transitions can be regarded equivalently as K a = 1 ← 0 transitions of a bent molecule or as l 5 = 1 ← 0 transitions of a linear molecule. The LMR data, combined with previous measurements on this molecule at microwave and submillimeter wavelengths, have been used to determine parameters of an asymmetric rotor Hamiltonian. The ν 5 band origin has been determined more accurately as 128.907 968 7 (40) cm -1 . In addition, it has been possible to characterize the electron spin splittings in the K a = 1 levels more reliably. Both 1 H and 14 N hyperfine splittings have been observed for the K a = 1 levels for the first time; they show that the nuclear spin-electron spin dipolar interactions are markedly noncylindrical. Values for the electron spin and rotational g-factors (g αα s and g αα r ) have also been determined.