Reactive and inelastic scattering in excited I2

Abstract

A great deal of data has been accumulated on electronic quenching and vibrational energy transfer in vibrational levels v′= 6, 15, 25, 43 and 51 of the B(³Π_o⁺_u) state of I₂. Analysis of these data permits us to draw a number of conclusions regarding the molecular potential curves and surfaces appropriate to this system. From the quenching data, we learn the shapes of the repulsive curves crossing through the B state curve. Spontaneous predissociation involves the ¹Π_1u curve, collisioninduced predissociation the ³Π_o⁺_u curve, and magnetically induced predissociation the ³Π_o^–_u curve.

From details of vibrational and rotational state changes upon collisions with third bodies, the shapes of the I—I—X potential surfaces can be deduced. We have analyzed the collisions by means of numerical integration of classical collision trajectories on these potential surfaces, and compared the predicted results with experimental data. Computer-animated film displays of some of these trajectories can be very helpful in interpreting the dynamics of the collisions.