High-Resolution IR Studies of Hydrogen Bonded Clusters: Large Amplitude Dynamics in (HCI)n

Published

July 1, 2001

Author(s)

M Farnik, S Davis, David Nesbitt

Abstract

Structural and dynamical information on small hydrooen bonded systems is revealed by high resolution IR spectroscopy of HCI dimer, trimerand tetramer. In (HCI)₂, four combination bands tentatively assigned to the van der Waals stretch Ņ₄ and geared band Ņ₅ vibrations are observed.The study focuses on two unexpected results: i) all of the observed bands are built only on the bound HCI stretch Ņ₂, and ii) the bandspredominantly originate from the 9-fold less populated upper tunneling level of the ground state. A model 3D quantum calculations arepresented to show, that both these surprising trends originate from the large amplitude tunneling dynamics in the dimer. The (HCI)₃ spectraare assigned and analyzed for multiple isotopomeric contributions. The spectral fit reveals large homogeneous line broadening indicating the excited state lifetime of difference} 1.6 ns and tentatively associated with dynamics of IVR induced trimer ring opening. Finally, first high resolution data on the HCI stretch fundamental spectrum of (HCI)₄ is presented.

Citation

Faraday Discussions

Volume

118

Pub Type

Journals

Keywords

cluster dynamics, HCI dimer, high resolution IR spectroscopy, hydrogen bond, tetamer, trimer

Citation

Farnik, M. , Davis, S. and Nesbitt, D. (2001), High-Resolution IR Studies of Hydrogen Bonded Clusters: Large Amplitude Dynamics in (HCI)_n, Faraday Discussions (Accessed February 7, 2026)