Journal of Molecular Spectroscopy 
                 -- Dec. 1995 -- vol.174, no.2, pp. 365-78

The CN mode of HCN: 
a comparative study of the variation of the transition dipole 
and Herman-Wallis constants for seven isotopomers and 
the influence of vibration-rotation interaction

Maki, A.; Quapp, W.; Klee, S.; Mellau, G.C.; Albert, S.

The electric dipole transition moments and vibration-rotation constants of
the CN stretching bands of H^12/C^14/N and six other isotopomers are
reported. Hot-band measurements show the vibrational dependence of the
constants. Infrared absorption spectra were measured with a Fourier
transform interferometer and a multipass absorption cell with a path length
of up to 240 m. The transition wavenumber measurements were used to derive
vibration-rotation constants, and the intensities of individual lines were
used to determine the transition dipoles and Herman-Wallis factors. The
unusually small transition dipole coupled with the large dipole moment of
HCN (2.98 D) results in very large values for the first Herman-Wallis factor
A, and distorts the shape of the intensity envelope of the band. These
measurements show how changes in the masses of the heavy atoms in the
molecule have a systematic effect on the transition dipole and on the
intensity pattern of the CN stretching band

Doc. Type Journal Paper ; Experimental
Publisher Academic Press Coden JMOSA3 ISSN 0022-2852

Classification codes A3370C; A3520J; A3370F

Indexing:
Fourier transform spectra; hydrogen compounds;
isomerism; isotope effects; rotational-vibrational states; 
spectral line intensity; transition moments;
CN mode; HCN; transition dipole; Herman-Wallis constants; 
isotopomers; vibration-rotation interaction; 
electric dipole transition moments; hot-band measurements; 
vibrational dependence; infrared absorption spectra; 
Fourier transform interferometer; multipass absorption cell; 
transition wavenumber measurements; line intensities; dipole moment;
intensity envelope; CN stretching band