In the linear infrared spectrum of phenyl cyanate, two peaks are observed in the spectral region of 2200-2300 cm^-1. These peaks are sensitive to solvent and thus have potential as a vibrational probe of local environment. Accordingly, it is important to first understand the origins of these transitions, and two dimensional infrared spectroscopy was applied for this purpose. The 2D-IR spectrum in the region of the OCN stretch frequency of phenyl cyanate exhibited the presence of the two transitions with strong coupling between them as shown by the presence of intense cross peaks, indicative of what is expected for a Fermi resonance. Interestingly, a strong correlation is also observed between the two transitions as well as similar anharmonic shifts in both the diagonal and off-diagonal peaks. These features are atypical for a traditional Fermi resonance. Thus, a discussion of the possible underlying mechanisms is presented.

Acknowledgements: Support from NSFCHE, and the RLBL facility grant (NIHRR 01348).