-H Pairs for the Planetary Atmospheres Structure: The Second Overtone Band
Modeling of Collision-Induced Absorption Spectra of H -H Pairs for the Planetary Atmospheres Structure: The Second Overtone Band
Y. Fu, A. Borysow (MTU,USA/NBIfAFG,DK)
Collision induced absorption (CIA) is known to constitute the major
component of the opacity of outer planets.
The work is of interest for modeling the atmospheres of Uranus and
Neptune. The spectra, centred around .83 
m, correspond to the
rotovibrational (RV) CIA in the second overtone band
(3-0) of H -H pairs, and are needed to further constrain
the vertical atmospheric structure of Uranus and Neptune.
Improved H -H 3-0 RV CIA data (intensity and spectral band
shape)
will be particularly important for that study. The second overtone
band of the RV CIA spectra is related with a
vibrational single transition
( 
) and double
transitions ( 
),
where 
are the vibrational
quantum numbers of two interacting H molecules (i=1 or 2).
The quantum mechanical methods are employed to compute the spectra
of 3-0 RV CIA of H -H pairs, with
newly developed ab initio induced
dipole moments [1] taken into account.
Our preliminary results also show good agreement with the existing
experimental data. More work is currently underway and we expect
the new results to be better than those presented here.
Future model of 3-0 spectra at the temperature range 20-300 K
will be distributed freely to all interested planetary
scientists.