The recombination of H-3(+) ions with electrons: dependence on partial pressure of H-2

We observed an increase in the effective recombination coefficient (alpha ( eff)) of the recombination of H-3(+) ions with electrons with a number dens ity of H-2, n(H-2). With increasing n(H-2) from 1 x 10(11) to 2 x 10(12) cm (-3) the alpha (eff) increased from 1.3 x 10(-8) to 1.5 x 10(-7) cm(-3) s(- 1). The dependence of alpha (eff) on n(H-2) indicates that the recombinatio n of H-3(+) ions in an afterglow plasma is a complex process in which colli sions with H-2 take place. It is stressed that at conditions corresponding to plasma in interstellar space the dissociative recombination of H-3(+) io ns is very slow with a rate coefficient alpha less than or equal to1.3 x 10 (-8) cm(3) s(-1). (C) 2000 Elsevier Science B.V. All rights reserved.