Knowledge Bank

The absorption spectra of $D2O$ and mixtures of heavy and light water vapor have been measured between 1.2 and $2.8\mu$. With the 15,000 line/inch grating, effective slits of about $.15cm-1$ could be used, resulting in considerably better resolution and greater detail than in any previously reported bands of $D2O$ and HDO. A multiple reflection cell with a path of 6 meters was used, heated to about $70\circ C$ in order to increase the density of the absorbing molecules. The analysis of the 101 and 111 bands of $D2O$ at 5373.6 and $6533.4cm-1$, respectively, have been verified and $extended1,2$ and we have observed and analyzed two new bands of this molecule, 011 at $3956.3cm-1$ and 201 at $7899.7cm-1$. The analyses have been extended to higher J-values than in previous work and yields improved rotational constants. We have also observed and measured a number of lines attributed to be HDO molecule, particularly in the regions centering about $4105cm-1(\nu 1+\nu 2$) and $5103cm-1(\nu 2+\nu 3$) and $6460cm-1$. The rotational analysis of these bands is in progress and will be reported on.