Photodissociaton of allyl-d2 iodide excited at 193 nm: Stability of highly rotationally excited H2CDCH2 radicals to C-D fission
- LBNL Library
The photodissociation of allyl-d2 iodide (H2C=CDCH2I) and the dynamics of the nascent allyl-d2 radical (H2CCDCH2) were studied using photofragment translational spectroscopy. A previous study found the allyl radical stable at internal energies up to 15 kcal/mol higher than the 60 kcal/mol barrier to allene + H formation as the result of a centrifugal barrier. The deuterated allyl radical should then also show a stability to secondary dissociation at internal energies well above the barrier due to centrifugal effects. A comparison in this paper shows the allyl-d2 radical is stable to allene + D formation at energies of 2-3 kcal/mol higher than that of the non-deuterated allyl radical following photolysis of allyl iodide at 193 nm. This is most likely a result of a combination of the slight raising of the barrier from the difference in zero-point levels and a reduction of the impact parameter of the dissociative fragments due to the decrease in frequency of the C-D bending modes, and the refore allene + D product orbital angular momentum. Integrated signal taken at m/e = 40 (allene) and m/e = 41 (allene-d1 and propyne-d3) shows a minor fraction of the allyl-d2 radicals isomerize to the 2-propenyl radical, in qualitative support of earlier conclusions of the domination of direct allene + H formation over isomerization.
- Research Organization:
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of Basic Energy Sciences. Materials Sciences Division and Chemical Sciences Division. Contract DE-AC03-76SF00098, USDOE Director. Office of Energy Research. Office of Basic Energy Sciences. Division of Chemical Sciences Contract DE-FG02-92ER14305 (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 837404
- Report Number(s):
- LBNL--54306
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 10 Vol. 119; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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