Energy Levels of Slightly Asymmetric Top Molecules

For the rotational analysis of the band spectra of slightly asymmetric tops it is convenient to have explicit expressions for the rotational energies in terms of the rotational quantum numbers. In the tables available at present the coefficients of the power series in the asymmetry parameter are only tabulated numerically for each individual rotational level. In the present work more general expressions are derived, giving the explicit dependence on J, K, and the asymmetry parameter ε (including terms up to ε5). First-order corrections for centrifugal distortion in terms of J, K, and ε have also been included.