Multiphoton association reaction He + H~+ → HeH~+ steered by ultra-short laser pulse

摘要

The multiphoton association reaction He + H~+ → HeH ~+ in the electronic ground state is investigated using the time-dependent quantum wave packet method. It is shown that the collision pairs He + H+ in continuum state transfer into ν = 0 state and then produce stable molecules HeH~+ through emission of two or three photons. The multiphoton transition takes place via intermediate states, and the transfer probability is determined by the collision energy and the intermediate states. The populations of the intermediate states and ν = 0 state can be controlled by the laser duration. The three-photon transition is more efficient than the two-photon transition for producing the molecule HeH+ in ν = 0 state.