Synchrotron-based infrared spectroscopy of the Coriolis perturbed v6 and v8 bands of trans-DCOOH

Previously, the Coriolis perturbed v6 and v8 bands of trans-DCOOH were analysed using a high-resolution infrared spectrum that only contained lines from the v6 fundamental; the v8 fundamental was too weak to be directly observed [Goh et al., Spectrochim. Acta A: Mol. Biomol. Spectrosc. 1999, 55, 1309]. Using a long pathlength multireflection cell and highly brilliant synchrotron radiation, we were able to observe the v8 fundamental with excellent signal-to-noise (in addition to the v6 fundamental). Analysis of the spectra using PGOPHER and SPFIT resulted in determination of an extensive set of molecular parameters, including two a-axis and four b-axis Coriolis coupling constants. The set features a significant refinement of the v8 =1 constants, with a band origin at 873.3848785(83) cm-1, which is --- 0.72 cm-1 higher than previously determined.

Automated summary

The v8 fundamental of trans-DCOOH molecule, which was previously too weak to be directly observed, has been successfully observed using a long pathlength multireflection cell and highly brilliant synchrotron radiation. A significant refinement of the v8=1 constants has been determined, with a slightly higher band origin compared to the previous determination.