Knowledge Bank

In our most recent measurements of infrared transitions of solid parahydrogen with low ortho impurities, using a White-type external multireflection system for a sample path length of 38 cm, we have detected new extremely weak features in the spectral region 7900 - 9900 $cm-1$. Among them are the single transition $$Y_{1\leftarrow 0}(0)\mbox{ at } 7991.85 (1)\mbox{ cm }^{-1}$$ and the double transitions $$Q_{1\leftarrow 0}(0)+Q_{1\leftarrow 0}(0)\mbox{ at } 8306.0 (1)\mbox{ cm }^{-1}$$$$U_{1\leftarrow 0}(0)+Q_{1\leftarrow 0}(0)\mbox{ at } 9407.67 (5)\mbox{ cm }^{-1}$$$$Q_{1\leftarrow 0}(0)+S_{1\leftarrow 0}(0)\mbox{ at } 9747.8 (1)\mbox{ cm }^{-1}$$$$U_{1\leftarrow 0}(0)+Q_{1\leftarrow 0}(0)\mbox{ at } 9837.34 (5)\mbox{ cm }^{-1}$$ The $Y1\leftarrow 0(0)$ transition is the second transition with $\Delta J=8$ observed in a molecular spectrum after the $Y0\leftarrow 0(0)$ $transitionb$ and is even weaker than the latter by an appreciable factor. Intensity parameters will be reported for all of these transitions. The data were taken at a sample temperature of 12.3 K.