A Note on Rotational Line Strengths in Slightly Asymmetric Rotors

Abstract

Direction‐cosine matrix elements for slightly asymmetric rotors are calculated by a second‐order perturbation treatment around the limiting symmetric rotor. This permits evaluation of the line strengths which are involved in calculations of absorption intensities, Stark effects, and nuclear‐quadrupole couplings in rotational spectra. Explicit formulas are derived for the first‐order terms.