Knowledge Bank

The pure rotational spectrum of $SiH4$ in the ground vibronic state has been observed with a Michelson interferometer. Thirteen lines have been clearly resolved in the region 50 to $135cm-1$ and identified as arising from pure rotational transitions from J = 10 $\to$ 11 to J = 22 $\to$ 23 inclusive. The evidence used to identify the mechanism as the centrifugal distortion electric dipole moment will be presented. The rotational constant $B0$ and the scalar distortion constant $Ds$ have been determined. The frequency analysis will be discussed in detail.