Experimental evaluation of the recombination rate of cations formed from fluoranthene

The recombination of electrons with polycyclic ions produced via ion-molecule reactions between N+ and N-2(+) precursor ions and fluoranthene (C16H10) has been studied at 300 K using a flowing afterglow Langmuir probe-mass spectrometer (FALP-MS) apparatus. The primary ions produced from these ion-molecule reactions consisted of pure hydrocarbon cations, and nitrogen-bearing compounds. These primary ions reacted further with fluoranthene to give adduct ions. As pyrene, which was present as an impurity in fluoranthene, attaches electrons, and for other reasons that are discussed in the paper, we have modeled the chemistry in our flow, in order to determine the recombination rates of the primary and the secondary ions with electrons. The fitted value for our primary ions is (2.5 +/- 1.5) x 10(-6) cm(3) s(-1) and the recombination rate for the secondary ions is close to the physical limit. (C) 2002 Elsevier Science B.V. All rights reserved.