ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
High resolution near infrared spectra of the two high frequency intramolecular modes in (DF)2 have been characterized using a slit-jet infrared spectrometer. In total, four pairs of vibration–rotation–tunneling (VRT) bands are observed, corresponding to K=0 and K=1 excitation of both the ν2 ("bound'') and ν1 ("free'') intramolecular DF stretching modes. Analysis of the rotationally resolved spectra provides vibrational origins, rotational constants, tunneling splittings and upper state predissociation lifetimes for all four states. The rotational constants indicate that the deuterated hydrogen bond contracts and bends upon intramolecular excitation, analogous to what has been observed for (HF)2. The isotope and K dependence of tunneling splittings for (HF)2 and (DF)2 in both intramolecular modes is interpreted in terms of a semiclassical 1-D tunneling model. High resolution line shape measurements reveal vibrational predissociation broadening in (DF)2: 56(2) and 3(2) MHz for the ν2 (bound) and ν1 (free) intramolecular stretching modes, respectively. This 20-fold mode specific enhancement parallels the ≥30-fold enhancement observed between analogous intramolecular modes of (HF)2, further elucidating the role of nonstatistical predissociation dynamics in such hydrogen bonded clusters. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.471604
