Two of the infra-red bands of Si${\mathrm{H}}_4$, originally measured by Steward and Nielsen, have been remeasured at much increased resolving power. In addition a new band near $13.0\mu$ has been located and measured. The bands have been identified as follows: their centers having been determined to be ${\nu }_2=930.9\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$, ${\nu }_3=2113.6\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$, and ${\nu }_4=819.3\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$. From a rotational analysis of these bands the equilibrium value of $B$ and the values of $B$ for the vibration states ${\nu }_2$, ${\nu }_3$, and ${\nu }_4$ have been determined, $B$ being $\frac{h}{8{\pi }^2\mathrm{Ic}}$. These have, respectively, the values $B_0=2.90\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$, $B^{\prime \prime }=2.87\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$, $B^{\prime }\left({\nu }_2\right)=2.96\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$, $B^{\prime }\left({\nu }_4\right)=2.79\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$. The values of $\zeta$ are found to be the following; ${\zeta }_4=\frac{1}{2}-{\zeta }_3=0.476\mathrm{}$. From the above data four independent relations existing between the generalized valence force constant are computed.

Close

PrevNext

View figure in article