Knowledge Bank

Nitrous acid (HONO) is an important source for OH radicals in tropospheric photochemistry.} Currently it is measured in the atmosphere using its ultraviolet absorption bands} but it has also been detected in the mid-infrared spectral region using a tuneable diode-laser.} In order to complete and extend previous laboratory work on the infrared fundamental bands of {\it trans}-HONO} and {\it cis}-HONO} and also of its deuterated species (DONO)} we have carried out a number of new spectroscopic studies, focusing on \begin{itemize} \item{the first high-resolution spectra of {\it trans-} and {\it cis-}HONO and -DONO in the far-infrared region (30--120 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$),} \item{the first high-resolution spectra and analysis of the $\nu 1$ bands of {\it trans-} and {\it cis-}DONO around 2600 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$,} \item{new high-resolution spectra and analysis of the Coriolis-interacting $\nu 5$ and $\nu 6$ bands of HONO around 600 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$.}} \end{itemize} In this talk we will present the main results and some comparisons with previous studies.