Nuclear Wavepacket Dynamics of Alkali Adsorbates on Metal Surfaces Studied by Time-Resolved Second Harmonic Generation

摘要

This paper reviews recent efforts to understand the dynamics of coherent surface vibrations of alkali atoms adsorbed on metal surfaces. Time-resolved second harmonic generation is used for the coherent excitation and detection of the nuclear wavepacket dynamics of the surface modes. The principles of the measurement and the experimental details are described. The main focus is on coverage and excitation photon energy dependences of the coherent phonon dynamics for Na-, K-, and Cs-covered Cu(111). The excitation mechanism of the coherent phonon has been revealed by the ultrafast time-domain technique and theoretical modelings.