Knowledge Bank

The collision-induced fundamental band of $D2$ in the pure gas at 77, 196 and 298 K was recorded for a number of gas densities up to 60 amagat with two 2 m absorption cells. The contributions to the intensity of the band from the short-range overlap and long-range quadrupolar interactions were separated by carrying out an analysis of the absorption profiles. For the $D2-D2$ molecular pairs, the overlap parameters, $\Lambda$ and $\rho$, which represent, respectively, the magnitude and range of the induced-overlap dipole moment, and $\mu overlap(\sigma )$, the induced dipole moment at the Lennard-Jones intermolecular diameter $\sigma$ were determined. Finally these parameters of $D2-D2$ were compared with those of $H2-H2$ and HD - HD, determined earlier in our $laboratory.1,2$