High-Resolution IR Studies of Hydrogen Bonded Clusters: Large Amplitude Dynamics in (HCI)n
M Farnik, S Davis, David Nesbitt
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.
cluster dynamics, HCI dimer, high resolution IR spectroscopy, hydrogen bond, tetamer, trimer
, Davis, S.
and Nesbitt, D.
High-Resolution IR Studies of Hydrogen Bonded Clusters: Large Amplitude Dynamics in (HCI)<sub>n</sub>, Faraday Discussions
(Accessed May 28, 2023)