The room temperature high resolution infrared spectrum of the (2 \nu_{3}) band of ({ }^{32} \mathrm{~S}^{16} \mathrm{O}{2}) in the 3.7 (\mu \mathrm{m}) region has been studied with a difference-frequency laser spectrometer and completely analyzed. The rotational levels of the upper state ( 002 ) have been reproduced to an accuracy of (\pm 0.00008) (\mathrm{cm}^{-1}) using a Hamiltonian matrix which explicitly takes into account the weak Fermi-type interaction coupling the rotational levels of the (002) state with those of (130) state yielding a band origin (\nu{0}=2713.382660(6) \mathrm{cm}^{-1}) and a complete set of rotational constants and a Fermitype interaction constant. This band exhibits a pronounced Herman-Wallis effect. However, the intensities have been very satisfactorily fit leading to a precise vibrational transition moment for the (2 \nu_{3}) band. Finally, a comprehensive set of line positions and intensities has been generated. For this band, the integrated band intensity has been found to be (S_{v}(T=296 \mathrm{~K})=9.81(20) \times) (10^{-5} \mathrm{~cm}^{-1} \mathrm{~Pa}^{-1} \mathrm{~m}^{-1}\left(0.0995(20) \mathrm{cm}^{-2} \mathrm{~atm}^{-1}\right)). A set of harmonic frequencies and vibrational anharmonic constants have been obtained. The effects of Darling-Dennison interaction appear to be very small. ic 1993 Academic Press. Inc.