Knowledge Bank

Our recent observation of very sharp spectral lines in solid $hydrogen1$ has suggested the possibility of conducting high resolution spectroscopy in molecular solids. Following this idea, rotationally resolved spectrum of $\nu 3$ and $\nu 4$ bands of CH4 impurity ($\sim 0.01\%$) in a $p-H2$ crystal have been studied using a 0.7 cm long cell at 4.2 K. Spectra were first recorded by a Bomem FTIR spectrometer at $0.1cm-1$ resolution. The major features agree well with earlier work on $CH4$ in solid $N2$ and noble-gas matrices.$\mathrm{<mrow\; data-mjx-texclass="ORD">2-4</mrow>}$ Higher resolution studies of the $\nu 4$ band using a diode laser spectrometer, however, have revealed a great many sharp lines with typical linewidth of $\sim 0.01cm-1$. The observed spectrum and preliminary analysis will be discussed.