High-resolution spectroscopic measurements of the nu(5) bending vibration-rotation band of HCCN in its (X)over-tilde(3)Sigma(-) state at 129 cm(-)1

Citation
Md. Allen et al., High-resolution spectroscopic measurements of the nu(5) bending vibration-rotation band of HCCN in its (X)over-tilde(3)Sigma(-) state at 129 cm(-)1, J MOL SPECT, 209(2), 2001, pp. 143-164
Citations number
43
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
JOURNAL OF MOLECULAR SPECTROSCOPY
ISSN journal
0022-2852 → ACNP
Volume
209
Issue
2
Year of publication
2001
Pages
143 - 164
Database
ISI
SICI code
0022-2852(200110)209:2<143:HSMOTN>2.0.ZU;2-N
Abstract
The HCCN radical is known to be a quasi-linear molecule in its ground tripl et state ((3)Sigma (-) in the linear configuration). Vibration-rotation tra nsitions in the HCC bending (nu (5)) fundamental band have been detected ar ound 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 resonance s. The observed transitions can be regarded equivalently as K-a = 1 <-- 0 t ransitions of a bent molecule or as l(s) = 1 <-- 0 transitions of a linear molecule. The LMR data, combined with previous measurements on this molecul e at microwave and submillimeter wavelengths, have been used to determine p arameters of an asymmetric rotor Hamiltonian. The nu (5) band origin has be en 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 H-1 and N-14 hyperfine splittings have been observed for the K-a = 1 levels for the first time; they show that the nucl ear spin-electron spin dipolar interactions are markedly noncylindrical. Va lues for the electron spin and rotational g-factors (g(s)(alpha alpha) and g(r)(alpha alpha) have also been determined. (C) 2001 Academic Press.