Journal of Molecular Spectroscopy 
         -- June 1995 -- vol.171, no.2, pp. 420-34

Intensities of hot-band transitions: HCN hot bands

Maki, A.; Quapp, W.; Klee, S.

A simple vibrational Honl-London-type formula for hot-band intensities is
tested by measuring the intensities of a number of vibrational transitions,
including many hot bands, for HCN. This vibrational intensity formula is
based on one- and two-dimensional harmonic oscillator functions and a
nonlinear electric dipole function that is expanded in a Taylor series with
respect to the normal coordinates. It is shown that, when this formula is
included, the observed transition dipoles for the bending hot bands differ
by only a few percent from the transition dipoles for the same quantum
number changes from the ground state. Infrared absorption intensity
measurements are given for the transition dipoles for the transitions 
01^1/0-00^0/0, 02^0/0-00^0/0, 03^1/0-00^0/0, 04^0/0-00^0/0, 10^0/0-01^1/0, 
12^0/0-00^0/0, and 20^0/0-00^0/0 
and the accompanying hot bands involving the lower states
v_2 =1, 2, and 3. This simple model is limited to well-behaved
systems, but would be useful for estimating the intensities of some
high-temperature spectra. For HCN the Herman-Wallis constants that are
quadratic in J (or m) are shown to be determined principally by the effect
of l-type resonance

Doc. Type Journal Paper; Theoretical or Mathematical; Experimental
Coden JMOSA3  ISSN 0022-2852

Classification codes A3320E; A3310G; A3520P; A3370F


Indexing:
hydrogen compounds; infrared spectra; spectral line intensity; 
vibrational states; 
hot band transitions; HCN; vibrational Honl-London-type formula; 
hot-band intensities; vibrational transitions;
room temperature spectrum; vibrational intensity formula; 
one-dimensional harmonic oscillator functions; 
two-dimensional harmonic oscillator functions; Taylor series; 
nonlinear electric dipole function; normal coordinates; 
transition dipoles; bending hot bands; quantum number changes;
ground state; IR absorption intensity; well-behaved systems; 
Herman-Wallis constants