Jump to main content
Jump to site search
PLANNED MAINTENANCE Close the message box

Scheduled maintenance work on Wednesday 27th March 2019 from 11:00 AM to 1:00 PM (GMT).

During this time our website performance may be temporarily affected. We apologise for any inconvenience this might cause and thank you for your patience.

Issue 2, 2018
Previous Article Next Article

The harpooning mechanism as evidenced in the oxidation reaction of the Al atom

Author affiliations


The harpooning mechanism has long been proposed for elementary reaction dynamics involving metals. It is characterized by an initial electron transfer (ET) process from the metal to the oxidant molecule. For the titled reaction Al + O2, the ET distance can be predicted to be 2.6 Å by simply calculating the energy difference between the ionization energy of the Al atom and the electron affinity of the O2 molecule. Hereby we experimentally derived the maximum impact parameter bmax of 2.5 ± 0.2 Å for the titled reaction, in consistency with the predicted ET distance. This derivation of bmax was achieved by using the crossed molecular beam experiment at a collision energy of 507 cm−1 (i.e. 1.45 kcal mol−1) with a high resolution time-sliced ion velocity imaging detection of the state-selective AlO products based on the (1 + 1) resonance-enhanced multiphoton ionization. The small rotational constant of the AlO(X2Σ+) radical (Be = 0.6413 cm−1) facilitated the formation of the AlO(v = 0) products in high rotational levels up to the energetically limited state, Nmax = 52, with an almost zero velocity mapping. Hence, in this extreme angular momentum disposal case, the collisional orbital angular momentum l was nearly completely channeled into the product rotational angular momentum as a consequence of the conservations of energy and angular momentum, offering a reaction system that breaks the restriction of kinematically favored mass combination in order to obtain information on the impact parameters. The present study yields the first direct derivation of bmax from the maximum rotational level of products under the experimental condition with the recoil energy ET ≈ 0. This, in turn, provides solid evidence in supporting the harpooning mechanism.

Graphical abstract: The harpooning mechanism as evidenced in the oxidation reaction of the Al atom

Back to tab navigation

Supplementary files

Publication details

The article was received on 30 Jul 2017, accepted on 01 Nov 2017 and first published on 02 Nov 2017

Article type: Edge Article
DOI: 10.1039/C7SC03314A
Citation: Chem. Sci., 2018,9, 488-494
  • Open access: Creative Commons BY license
  •   Request permissions

    The harpooning mechanism as evidenced in the oxidation reaction of the Al atom

    F. Li, C. Dong, J. Chen, J. Liu, F. Wang and X. Xu, Chem. Sci., 2018, 9, 488
    DOI: 10.1039/C7SC03314A

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author