Mechanism and kinetics of formation and decay of HeH(B Π) and HeD(B Π) molecules due to recombination of H(2p), D(2p), and He atoms

Experimental and theoretical investigations were made of the elementary processes occurring in the course of recombination of H(2p), D(2p), and He atoms at T = 293 K. The decay of the vibrational levels of the B ²Π state of the HeH and HeD molecules was greatly influenced by the collision-induced predissociation at a rate close to gaskinetic, the chemiluminescence spectrum due to the reactions H (2p) + He and D(2p) + He was located in the spectral range λ = 121.6–130 nm irrespective of the He pressure, and the kinetics of the three-particle recombination at pressures P(He) > 200 Torr became bimolecular. The rate constant of the chemiluminescence due to this process did not exceed 2.5 X 10 ^– 14 photons·cm³·particle ^– 2·s ^– 1 at any pressure of the reagents.