Pulsed molecular beam spectra of the CH4-OCS complex have been recorded using both a molecular beam infrared diode laser and a Fourier transform microwave spectrometer. Analysis of the spectrum yields a near T shape structure with a centre of mass separation of 3.83 Å and a CH4 centre of mass-OCS centre of mass-oxygen angle of 73°. Splittings attributed to the internal rotations of methane within the complex have been observed in the microwave spectrum. The rotational constants of the complex for the A and T librational states of CH4 were determined. The differences (T - A) in the rotational constants were ΔA = 0.35, ΔB = -1.60 and ΔC = -1.85 kHz.
