Knowledge Bank

High resolution infrared absorption spectra of the weakly bonded $OCS\cdot \cdot HX$ complexes have been observed in the $2055cm-1$ region. Infrared spectra of $SCO-HF,SCO-H35Cl,SCO-H79Br$ and $SCO-H81Br$ were obtained on a rapid scan diode laser spectrometer which incorporate a pulsed 12 cm long $\times 200$ micron wide slit nozzle. The spectral features for all three dimers consists of regularly spaced features characteristic of linear hydrogen bonded structures. Ground state rotational constants of SCO-HF and $SCO-H35$Cl agree with previous microwave $measurements.1.2$ It is interesting to note that SCO-HBr complex exhibits a linear structure instead of the bent structure found in $CO2$-HBr and $N2O-HBr$. In addition, the band origin shifts (i.e., $\Delta \nu =\nu 0$ (complex)-$\nu 0$(monomer) of the OCS-HX species are quite different from their $CO2$ and $N2O$- $analogs.3,4$ The band origin shifts associated with $CO2$-HX and $N2O$-HX follows the trend $-HF>-HCl>-Br$. In contrast, our infrared results show that the band origin shifts by $-6.8,-7.3,-7.2cm-1$ for SCO-HF, SCO-HCl and SCO-HBr, respectively.