Knowledge Bank

Crossed beams have been combined with the laser-pump, dispersed fluorescence probe technique to study inelastic collisions. Preliminary results on the $I2\mathrm{<mrow\; data-mjx-texclass="ORD">\ast </mrow>}(BOu\mathrm{<mrow\; data-mjx-texclass="ORD">+</mrow>})$ + He system were reported in this conference last year. The spectroscopy has now provided many state-to-state vibrationally inelastic cross sections for both He and other target gases. The collision energy dependence as well as the initial vibrational state dependence of the cross sections will be presented. Those cross sections give new insights into the collisional dynamics. Landau-Teller modeling and classical trajectory calculations have both been compared with the data. Both replicate aspects of the data, and by some standards, both are fairly successful. The precision of the data are high enough, however, to reveal clearly the inadequacies of the present treatments. The collision dynamics will be discussed in detail based on the classical trajectory calculations.