Theoretical prediction of ultrahigh vibrational excitation using infrared picosecond pulse trains: Coherent absorption of several photons each of a different frequency

Using an IR picosecond pulse train, ultrahigh vibrational excitation in a Morse oscillator is achieved. Following a suggestion by Paramonov and Savva, pulse-train parameters can be chosen such that within 100 pulses (about 20 ps) there is significant excitation into the eighth excited vibrational state. We improve on their work by (1) using physically realistic matrix elements and potential parameters; (2) using Floquet theory to more efficiently perform the numerical calculation; (3) discussing the molecular excitation sensitivity to pulse-train parameters: pulse spacing, pulse width, central laser frequency, and peak laser fluence; and (4) showing that the vibrational excitation is a coherent multicolor, multiphoton process.