Electronic Resource
College Park, Md.
:
American Institute of Physics (AIP)
The Journal of Chemical Physics
115 (2001), S. 5823-5829
ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
We have investigated the spectroscopy and photochemistry of Zn+(C2H4) in an angular reflectron time-of-flight mass spectrometer. We identify four absorption bands in the spectral range 220–550 nm. These bands are assigned to radiative transitions in the bimolecular complex correlating with Zn-centered and ethylene-centered absorptions, and with Zn–ethylene photo-induced charge transfer processes. The lowest energy band, assigned as 1 2B2←1 2A1, is a weak continuum consistent with a large geometry change and fast predissociation. The higher energy 1 2B1←1 2A1 band shows a long progression in the intermolecular stretch with a mode frequency of ωe=333.7 cm−1. The spectroscopic results, including partially resolved rotational structure, are consistent with a weakly bound, π-bonded complex in C2v symmetry. A Birge–Sponer analysis gave an estimate for the dissociation energies of the excited 1 2B1 state as De′=2.76 eV and the ground 1 2A1 state as De″=0.86 eV. A second structured band at still higher energies is tentatively assigned as 2 2B2←1 2A1 and shows activation of higher frequency intramolecular ethylene modes. Zn+ and C2H4+ fragment ions are observed over most of the spectral range. At higher energies (λ〈250 nm) we also see a significant branching to reactive products C2H2+ and C2H3+ that result from charge transfer accompanied by C–H bond cleavage. We propose a reaction mechanism that involves coupling through an excited charge-transfer state followed by C–H bond insertion. © 2001 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1399299
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