Sensitive fluorescence spectroscopy of jet cooled 15NO2

A spectroscopic setup designed for high resolution spectroscopy of jet cooled molecules is described. The primary features of the new setup are an exceedingly low gas consumption and a high detection efficiency, which are achieved by optimizing the detection geometry of the time gated fluorescence in combination with a special piezo valve. This makes the setup particularly suitable for studying expensive gases that come in small supply. The performance of the setup is demonstrated on the first A2B2 ← X2A1 rovibronic transitions of 15N16O2 measured in a jet. A rotational analysis is given for a couple of different bands. In addition, an exceptionally strong band with band origin around 14 850 cm−1 is reported that is of interest particularly for atmospheric applications. The 15N16O2 gas consumption is as low as 0.025 mg or 0.5 μmol/cm−1 spectral range.