The state-to-state predissociation dynamics of OC–HF upon HF stretch excitation

Abstract

Photofragment angular and state distributions have been measured following the vibrational predissociation of the OC-HF complex. An F-center laser is used to pump the fundamental H-F stretching vibration of the complex and a second F-center laser is used to probe the rotational states of the HF fragment as a function of recoil angle. The complex dissociates via two different sets of channels, one that produces v CO ϭ1, J HF ϭ6,5,4 ͑intermolecular V -V transfer͒ and the other v CO ϭ0, J HF ϭ11 ͑V -R transfer͒. Analysis of the data gives correlated final state distributions, as well as an accurate value for the dissociation energy (D 0 ) of the complex, namely 732Ϯ2 cm Ϫ1 .

Spectroscopy of the OC–HF hydrogen-bonded complex at vHF=3

“…[1][2][3][4][5][6] The global equilibrium structure is found to be linear with the atomic arrangement of OC-HF from its microwave spectrum, 3,4 in agreement with almost any theoretical prediction. [7][8][9] The analysis of state-to-state dissociation dynamics 1 determined the binding energy D 0 ϭ732 Ϯ2 cm Ϫ1 , which may be compared to 398Ϯ2 cm Ϫ1 for the isoelectronic species N 2 -HF also measured by Bemish et al 10 The vibrational states are labeled as (v 1 v 2 v 3 v 4 v 5 ), where v 1 is the HF stretch, v 2 is the CO stretch, v 3 is the van der Waals or hydrogen bond stretch, v 4 is the HF intermolecular bend, and v 5 is the CO intermolecular bend.…”

“…From the unimolecular decomposition point of view, this observation reinforces a picture of the vibrational mode-specific character of HF complexes. Comparison of linewidths in (HF) 2 for v 1 and v 2 , which show factors of 30 difference, as well as the level with higher energy dissociating more slowly is perhaps the clearest and most dramatic display of mode specificity. Here we note that from a statistical RRKM theory, 45 at a vibrational excitation energy of more than 10 000 cm Ϫ1 , the density of states of the complex is so high that there should not be any type of mode selectivity.…”

Overtone spectroscopy of H2O clusters in the vOH=2 manifold: Infrared-ultraviolet vibrationally mediated dissociation studies

“…Nevertheless, these studies make simple predictions and highlight some interesting directions for further exploration with quantum state resolution in the ejected H 2 O, as perhaps could be studied by IR photofragmentation recoil spectroscopy. 56,57…”

Spectroscopy and energetics of the acetylene molecule: dynamical complexity alongside structural simplicity

“…N 2 or C 2 H 2 scattered on one side of the incident molecular beam direction and HF on the other) and identified more reliably than is possible in zero field. Comparable PHOFAD studies of electrically oriented complexes have also been performed in the cases of CO 2 -HF [43,273], CO 2 -HCl [274], C 2 H 2 -HCl [39,43], OC-HF [43,275], and HCN-HF [43,276]. Oudejans and Miller have provided a critical tabular summary of complex dissociation energies D 0 , experimentally determined in molecular beams by various forms of translational spectroscopy including PHOFAD [43].…”