High temperature collisional energy transfer in highly vibrationally excited molecules. III: Isotope effects in tert-butyl bromide systems

✍ Scribed by Trevor C. Brown; Keith D. King; Robert G. Gilbert

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 643 KB
• Volume: 20
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550200705

✦ Synopsis

Changes in the magnitude of (AEdOwn), the average downward collisional energy transferred between a highly vibrationally excited reactant molecule and an inert bath gas, upon perdeuteration of the substrate are reported for tert-butyl bromide dilute in Ar, Kr, N,, and CO,. The technique of pressure-dependent very low-pressure pyrolysis (VLPP) was used to obtain the absolute values of (AEdown), which are for C4H9Br, 230 (Ar), 285 (Kr), 270 (N2), and 365 (COz) while for C4DgBr, 200 (Ar), 250 (Kr), 220 (Nd, and 335 (CO,), all in cm-' a t ca. 720 K. The estimated uncertainties in these values are ca. +lo%. These observed (AEd,,,) values and trends found with results from this series of isotope studies, are compared with current theoretical models. Extrapolated high-pressure temperature-dependent rate coefficients ( s -* ) for the thermal decomposition of reactant are 10'38'03 exp(-175 _f 8 kJ mol-'/RT) for C4H9Br and 10'4.3'03 exp(-183 t 8 kJ mol-'/RT) for C4D9Br. These results are in accord with other studies and the expected isotope effect.