ISSN:
1432-0649
Keywords:
PACS: 82.30.Fi
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract. Ammonia ions (NH3 +) are prepared in two internal states of nearly the same energy, a state with five quanta in the umbrella bending mode (Eint=0.60 eV) and another state with one quantum in the all-symmetric stretch and two quanta in the umbrella bending mode (Eint=0.63 eV). These ions are allowed to react with different neutral reagents, and the product ions are mass analyzed and detected. For each reaction, the product branching ratios are measured as a function of center-of-mass collision energy. Whereas reactions with D2O, D2, and CD4 are found to be uninfluenced by the state preparation of the NH3 + reagent, reactions with ND3, partially deuterated methylamine (CD3NH2), and tetrahydrofuran (c-(CH2)4O)show varying degrees of mode selectivity, the reaction with tetrahydrofuran to the least extent. We suggest that mode selectivity in these ion–molecule reactions should be a general feature when the charge transfer channel is energetically open, the geometry of the reagent ion differs markedly from the corresponding neutral, and different reaction pathways compete for product production.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003400000381
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