Direct frequency comb spectroscopy of HCN to evaluate line lists

We report direct frequency comb spectroscopy of the 2 nu(1) band of (HCN)-C-13 in the short-wave infrared (lambda = 1.56 mu m) towards experimental validation of molecular line lists that support observatories like JWST. The laboratory measurements aim to test spectral reference data generated from an experimentally accurate potential energy surface (PES) and an ab initio dipole moment surface (DMS) calculated from quantum chemistry theory. Benchmarking theory with experiment will improve confidence in new astrophysics and astrochemistry inferred from spectroscopic observations of HCN and HNC. Here we describe our instrumentation and initial results using a cross-dispersed spectrometer with a virtually imaged phased array (VIPA).

Automated summary

We conducted direct frequency comb spectroscopy on the 2 nu(1) band of (HCN)-C-13 in the short-wave infrared region (lambda = 1.56 mu m) to experimentally validate the molecular line lists used in observatories like JWST. Our laboratory measurements aimed to test spectral reference data generated from accurate potential energy surface (PES) and ab initio dipole moment surface (DMS) calculated using quantum chemistry theory. Comparing theory with experiment will enhance confidence in the interpretation of spectroscopic observations of HCN and HNC in astrophysics and astrochemistry. In this paper, we describe our instrumentation and present initial results obtained using a cross-dispersed spectrometer with a virtually imaged phased array (VIPA).