No abstract

No abstract

No abstract

A description and summary of the latest edition of the AFGL HITRAN molecular absorption parameters database are presented. This new database combines the information for the seven principal atmospheric absorbers and twenty-one additional molecular species previously contained on the AFGL atmospheric absorption line parameter compilation and on the trace gas compilation. In addition to updating the parameters on earlier editions of the compilation, new parameters have been added to this edition such as the self-broadened halfwidth, the temperature dependence of the air-broadened halfwidth, and the transition probability. The database contains 348043 entries between 0 and 17,900 cm(-1). A FORTRAN program is now furnished to allow rapid access to the molecular transitions and for the creation of customized output. A separate file of molecular cross sections of eleven heavy molecular species, applicable for qualitative simulation of transmission and emission in the atmosphere, has also been provided.

A Hamiltonian for vibration and rotation in polyatomic molecules is described which is general for large and small amplitude motion and most choices of rotating axes. An analysis of the effect of a change in the definition of the rotating axes is presented and the convergence properties of perturbation expansions of the Hamiltonian are discussed. Some rotation—vibration terms converge slowly in an arbitrary set of axes, and the effect of these terms is shown to be equivalent to rotation from the original set of axes to a new set of axes in which the coriolis terms are minimized. Ways to find this new set of axes are discussed, and application of the results of this work to the microwave spectra of several molecules is presented.