Knowledge Bank

The results of recent experiments of HDO pressure broadened by $O2$, $N2$, He, and $He2$ will be presented. The 2$\mathrm{<mrow\; data-mjx-texclass="ORD">1.1</mrow>}$-2$\mathrm{<mrow\; data-mjx-texclass="ORD">1.2</mrow>}$, 3$\mathrm{<mrow\; data-mjx-texclass="ORD">1.2</mrow>}$ and 7$\mathrm{<mrow\; data-mjx-texclass="ORD">3,4</mrow>}$ -6$\mathrm{<mrow\; data-mjx-texclass="ORD">4,3</mrow>}$ transitions of water (HDO) were studied between 90 K and 600 K. Results for the temperature dependence of the pressure broadening parameters and collisional cross sections are discussed. The transitions available for study in HDO allow a comparison of pressure broadened lines with widely different lower state energies. Trends in the 300K broadening parameter and temperature coefficient are noted. Low temperature measurements were made in a collisionally cooled $cell1$with a continuously variable temperature between 80 K and 300 K. Static measurements were made in a quartz cell enclosed in an oven with a continuously variable temperature between 80 K and 600 K.