High-resolution infrared spectroscopy of carbon dioxide dimers, trimers, and larger clusters

Abstract

From 1984 to 1996 there was rapid progress in the spectroscopy of CO₂ dimers and trimers, but since then little work has appeared. Here we report a number of new high-resolution infrared results. For the dimer, a combination band provides the first experimental intermolecular vibrational frequency, and ¹³C isotopic spectra clarify the role of resonant and non-resonant vibrational shifts. For the cyclic trimer, a new parallel combination band involving an out-of-plane intermolecular mode is observed, and various ¹³C isotope results are analysed. In addition to these dimer and trimer results, the spectra also contain features which must be due to larger (CO₂) _N clusters in the range N ≈ 5–15.

Keywords:

• carbon dioxide
• dimer
• trimer
• cluster
• spectroscopy

Acknowledgements

We thank L. Murdock for technical assistance, J. Norooz Oliaee and F. Mivehvar for some of the measurements, and S.R. Gadre for some unpublished results. Many of our results were greatly facilitated by use of PGOPHER, and we are pleased to acknowledge C.M. Western for helpful advice and program updates. We gratefully acknowledge the financial support of the Natural Sciences and Engineering Research Council of Canada.

Notes

Note

All figures can be viewed in colour online.