Perturbation of electronic potentials by femtosecond pulses — time resolved photoelectron spectroscopic study of NO multiphoton ionization

Femtosecond time-resolved photoelectron spectroscopy (TRPES) is applied to the study of 2 + 1 multiphoton ionization process in nitric oxide via the γ, β and δ-systems. Selective excitation of a given vibronic state is demonstrated by tuning the intensity of the femtosecond pulse. Rapid modulation in the TRPES spectrum is observed and attributed to the temporal perturbation of the Rydberg—valence interaction by the femtosecond pulse. The experiment shows that significant distortion to an electronic surface can be introduced by femtosecond laser pulses commonly available in modern laboratories. Possible application of the phenomenon to laser controlled chemistry is discussed.