Spin–orbit induced association under ultrafast laser pulse control

The possibility of spin–orbit induced association reactions controlled by optimized femtosecond laser pulses is demonstrated for the example of Br+(3P)+H(2S)→HBr+(X2Π/A2Σ+) association. The nuclear wavepacket dynamics is simulated on the basis of ab initio data for HBr+. To achieve permanent, vibrationally state–selective association, both a Feshbach resonance between collision and vibronic energies and optimal timing between spin–orbit induced and laser pulse assisted transitions are important. The novel method can be effective even when direct photoassociation is forbidden.