This paper pertains to rotational coherence spectroscopy, a time-domain method of high resolution rotational spectroscopy based on the quantum beat phenomenon. We present a brief discussion of the theoretical basis of the method and a consideration of its advantages over spectral domain methods. We also present experimental results on two species - 1,2-diphenyl acetylene and the tryptamine-(methanol) hydrogen-bonded complex - as further examples of the utility of the method in studies of large species.© (1990) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.