Band model parameters for the parallel bands of linear triatomic molecules—I. Theory

Generalized equations are developed for computing the band model parameters ($\text{S}\text{d}$), ($\text{S}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{/D}$) and ($\text{1}\text{d}$) for the parallel bands of linear triatomic molecules. The convergence of these band-model parameters as a function of the number of quantum states included in a computation is discussed for the 4.3 μm CO₂ band at various temperatures and wavenumbers. Comparisons are made to previous theoretical calculations for the 4.3 μm CO₂ band, where it is shown that an insufficient number of quantum states was included in the earlier work to insure convergence of the band-model parameters.