High-resolution overtone spectra of molecular complexes

Abstract

A high-resolution spectrum of the acetylene–water complex has been recorded in the overtone range. Two bands of C₂H₂–D₂O were analysed, corresponding to the overtone excitations of either the acetylene or the water units. The vibrational shifts and the upper states rotational constants were retrieved, demonstrating that the geometry of the complex is only slightly modified by the excitation. A larger linewidth was observed for the 2CH band than for the 2OD + DOD band, probably due to the direct coupling of the 2CH excitation with the dissociation coordinate.

Keywords:

• molecular complex
• acetylene
• water
• overtone
• high resolution

Acknowledgements

This work was sponsored by the Fonds National de la Recherche Scientifique (FNRS), the ‘Action de Recherches Concertées de la Communauté française de Belgique’ and the Belgian Federal Science Policy Office (contract SD/CS/07A, Advanced Exploitation of Ground-Based Measurements for Atmospheric Chemistry and Climate applications – II). We would like to thank Dr. N. Moazzen-Ahmadi (Calgary) for pointing out the presence of the D₂O band in the 1.5 µm range.