Conical intersections induced by light: Berry phase and wavepacket dynamics

Overview & Synopsis

Conical intersections (CIs) play an important role in the nonadiabatic molecular processes. Characterizing and localizing them is important for describing and controlling electronic energy ow in molecules. It is known that no conical intersection appears in free diatomic systems. In earlier works [ J. Phys. B. 41, 221001 (2008), J. Phys. B. 44, 045603 (2011) ] it was pointed out that CIs can be formed both by standing and running laser waves even in diatomics. The energetic and internuclear positions of these CIs depend on the laser frequencies while the strength of their nonadiabatic couplings can be modied by the eld intensities. In this work we calculate the topological or Berry phase of the light-induced CI in the Na2 molecule. The presence of this phase is a clear ngerprint of the laser-induced CI. In addition, we perform a detailed study of the wave packet propagation and discuss eects which reect the signicant presence of the laser-induced CI.