Studies on the effects of nonadiabatic behavior during the course of HBr photolysis

摘要

From quantum mechanical simulation, photodissociation of hydrogen bromide (HBr) in its first UV absorption continuum (A band) taking place upon excitation has been studied. The absorbencies are inferred from techniques of Forurier transformation. On that foundation, the branching fractions for the spin-excited Br* (2P_1/2) channel at enormous photon frequencies are gained. Moreover, the relevant MOs have been analyzed to obtain more information about the dissociation process within the framework of the time-dependent density functional theory. The results unravel that the possibility of intersystem crossing does exist in the photodissociation course, which involve the coupling of the a3Π₀ + and A1Π₁ potential surfaces. The prediction of the wavelength dependence of the anisotropy parameter β agrees with the experiment within a major part of A band, which provides an insight into the reaction dynamics and the transiton probability is conjectured to be larger when channels approach each other, notwithstanding a steady decline towards the red wing of spectrum. Keywords Nonadiabatic behavior - Photolysis - Angular distribution