Rate coefficients and integral cross-sections for the reaction of B(P-2(J)) atoms with acetylene

The reactivity of B(P-2(J)) atoms towards C2H2 (C2D2) has been investigated using complementary experimental methods. Kinetic measurements performed with C2H2 over the range T = 23 - 295 K have yielded thermal rate coefficients which temperature dependency is well described by the following expression: k = 3.21 x 10(-10) (T/300)(-0.50) exp(-37/T) cm(3) molecule(-1) s(-1) in the experimental temperature range. Crossed beam experiments performed with C2D2 co-reagent over the range of relative translational energies E-T = 0.35 - 9.4 kJ mol(-1) have yielded integral cross sections for D(S-2(1/2)) production that are proportional to (E-T)(-0.97 +/- 0.02) above 1 kJ mol(-1). The excellent agreement between both sets of data is discussed in terms of mechanism, invoking the presence of a very weak entrance barrier.